ENGINEERING AND CFD

Engineering and CFD

Principal Investigator: Lukas Fischer , Bundeswehr University Munich, Department of Aerospace Engineering, Thermodynamic, Neubiberg, Germany

HPC Platform used: SuperMUC-NG at LRZ

Local Project ID: pn73ji

The air stream in a gas turbine is firstly compressed and delivered to the combustion chamber, where fuel is mixing in and burnt, releasing a tremendous amount of heat. The hot turbulent bumt gases expand through the turbine placed downstream and the exhaust nozzle. Over the last decades, the turbine inlet temperature has increased because this leads to a higher efficiency of the gas turbine. The temperature of the hot gas of the combustion chamber (2,200 °C) and turbine section (1,700 °C) surpasses the material's maximum temperature limit (900 °C). In order to safeguard the metal walls from damage, they are covered by a ceramic thermal barrier coating (TBC) but this is not sufficient to protect the metal components from overheating.

Engineering and CFD

Principal Investigator: Francesca Pelusi, Fabio Guglietta , Helmholtz Institute Erlangen-Nürnberg for Renewable Energy, Forschungszentrum Jülich, Germany

HPC Platform used: JUWELS Cluster at JSC

Local Project ID: POLPS

Liquid metals like Gallium (Ga) are a promising platform for catalytic devices such as SCALMS (Supported Catalytically Active Liquid Metal Solutions). Ga develops an oxidized surface layer (Ga₂O₃), which is known to have a major impact on droplet dynamics and technological performance.

We simulate droplets via a coupled Immersed Boundary Lattice-Boltzmann (IBLB) method, for which we introduce a generalized model for elastic properties of the membrane, to cover properties of oxidized droplets and beyond [1].

Engineering and CFD

Principal Investigator: Dr. Matthias Meinke , RWTH Aachen, Aerodynamisches Institut, Aachen, Germany

HPC Platform used: JEWELS Booster of JSC

Local Project ID: GCS-MINION

The mitigation of aircraft noise is a major goal of the society to reduce the harmful effects on the human health and cognitive performance when exposed to a pervasive noise level. Although several events in the past have temporarily reduced the air traffic, a long-term constant growing rate if 4- 8%p.a. of passengers has been observed in the recent years. New concepts for on-demand Urban Air Mobility evolve and thus, additionally implying an extension of urban areas. Coping with this trend, the ACARE 1 defined ambitious goals of Europe’s vision for aviation for the year 2050 in the Flightpath 2050.

Engineering and CFD

Principal Investigator: Prof. Holger Foysi , Chair of Fluid Dynamics, Universität Siegen, Siegen, Germany

HPC Platform used: JUWELS Booster of JSC

Local Project ID: osccompchannel

Reducing drag in engineering type flows is of paramount importance. Various approaches and configurations were tackled in the past, mostly, however, dealing with incompressible flow. In this project, researchers at University of Siegen were investigating a specific oscillation type control method for sub- and supersonic channel flow, a configuration where the fluid domain is restricted by cooled lower and upper walls.

Engineering and CFD

Principal Investigator: Dr. Manuel Keßler , Universität Stuttgart, Institut für Aerodynamik und Gasdynamik (IAG), Stuttgart, Germany

HPC Platform used: Hawk/HAZELHEN of HLRS

Local Project ID: HELISIM

The helicopters & aeroacoustics group of the Insitute of Aerdynamics and Gasdynamics at the University of Stuttgart continues to develop their well-established and validated rotorcraft simulation framework. In addition to vibration prediction, noise reduction, and maneuver flight developments, new application areas like air taxis and distributed propulsion emerge out of industrial needs and fundamental research questions.

Engineering and CFD

Principal Investigator: Prof. Dr. Heinz Pitsch , Institute for Combustion Technology, RWTH Aachen University, Aachen, Germany

HPC Platform used: Hawk of HLRS

Local Project ID: SootDNS

A direct numerical simulation (DNS) of a turbulent air/ethylene jet was conducted to further understand soot oxidation at relevant combustion regimes. The DNS computational domain comprised 1.5 billion points, which integrated a detailed soot model and a chemical kinetic mechanism that involved 41 chemical species. Diverging from previous works primarily focused on soot formation, this project investigates the later stages of soot evolution, particularly its oxidation in turbulent flames. The roles of OH radicals and molecular oxygen in oxidizing soot particles, along with their distribution across mixture fraction space, were analyzed. Leveraging the dataset, an assessment of existing subfilter models for soot-gas phase interaction,…

Engineering and CFD

Principal Investigator: Prof. Dominique Thévenin , Otto von Guericke Universität, Institut für Strömungstechnik und Thermodynamik, Magdeburg, Germany

HPC Platform used: Hawk of HLRS

Local Project ID: CRYSALB

Lattice Boltzmann method (LBM) with phase-field model has been performed to investigate the growth habit of a single ice crystal. Given the multitude of growth habits, pronounced sensitivity to ambient conditions and wide range of scales involved, snowflake crystals are particularly challenging. Only few models are able to reproduce the diversity observed regarding snowflake morphology. It is particularly difficult to perform reliable numerical simulations of snow crystals. Here, we present a modified phase-field model that describes vapor-ice phase transition through anisotropic surface tension, surface diffusion, condensation, and water molecule depletion rate.

Engineering and CFD

Principal Investigator: Prof. Dr.-Ing. Heinz Pitsch , Institute for Combustion Technology, RWTH Aachen University, Germany

HPC Platform used: SuperMUC-NG of LRZ

Local Project ID: pn29gu

A direct numerical simulation (DNS) with finite rate chemistry has been performed to investigate the influence of flame-wall interaction (FWI) on carbon monoxide (CO) emissions in very lean turbulent premixed methane flames. CO emissions are affected by the mean strain rate of the turbulent flow, the FWI, and the interactions of the flame with the recirculation zones of the flow. The CO production and consumption in the turbulent flame differ strongly from the reaction rates in a freely propagating flame.

Engineering and CFD

Principal Investigator: Prof. Dr. Günther Meschke , Institute for Structural Mechanics Department of Civil and Environmental Engineering, Ruhr University Bochum

HPC Platform used: Juwels at JSC

Local Project ID: CHBU28

Using a combination of computational simulations and experiments, researchers at the Ruhr University Bochum are investigating the complex dynamics that govern how cracks propagate in brittle and quasi-brittle materials, such as glass and hard rock. The work has implications both for mining and mineral extraction, as well as designing safer buildings.

Engineering and CFD

Principal Investigator: Prof. Dr. Jörg Schumacher , TU Ilmenau

HPC Platform used: JUWELS at JSC

Local Project ID: mesoc

A team of researchers led by TU Ilmenau Professor Jörg Schumacher have been using the JUWELS supercomputer at the Jülich Supercomputing Centre to run highly detailed direct numerical simulations (DNS) of turbulent flows at the so-called mesoscale—the intermediate range where both small-scale turbulent fluid interactions and large-scale fluid dynamics converge.

Engineering and CFD

Principal Investigator: Dr. Bernd Mohr , Forschungszentrum Jülich

HPC Platform used: JUWELS at JSC

Local Project ID: SCALASCA

The Scalasca project brings together HPC experts in pursuit of new ways to measure and improve performance for increasingly large, heterogeneous architectures.

Engineering and CFD

Principal Investigator: Prof. Andreas Kempf , Universität Duisburg-Essen

HPC Platform used: SuperMUC-NG at LRZ

Local Project ID: pn68nu

This project collates individual applications from the Fluid Dynamics group at Duisburg-Essen University. The subprojects include the investigation of phenomena from the fields of nanoparticle synthesis, supersonic flows and stratified burners using LES, DNS and direct chemistry.

Engineering and CFD

Principal Investigator: Detlef Lohse , Max Planck Institute for Dynamics and Self-Organization, Göttingen

HPC Platform used: SuperMUC-NG at LRZ

Local Project ID: pr74sa

A tremendous variety of physical phenomena involve turbulence, such as the dynamics of the atmosphere or the oceans, avian and airplane flight, fish and boats, sailing, heating and ventilation, and even galaxy formation. Turbulent flow is characterized by chaotic swirling movements that vary widely in size, from sub-millimeter, over the extent of storm clouds, to galactic scales. The interaction of the chaotic movements on different scales makes it challenging to simulate and understand turbulent flows. Turbulent thermal convection plays an important role in a wide range of natural and industrial settings, from astrophysical and geophysical flows to process engineering.

Engineering and CFD

Principal Investigator: Martin Oberlack , TU Darmstadt

HPC Platform used: SuperMUC-NG at LRZ

Local Project ID: pn73fu

Turbulence has been a topic of research for many decades and finds its applications in many aspects of life. Still, turbulence is not fully understood up until today. The Navier-Stokes equations, which are used to describe the motion of viscous fluids, do not have a general analytical solution. Consequently, many researchers work with specific canonical cases to understand turbulence better. In the recent years as computers became increasingly powerful, more and more direct numerical simulations (DNS) have been conducted to solve turbulent flows. The goal of this project is to validate the scaling laws that have been derived for a turbulent round jet using Lie-symmetry analysis with numerical data.

Engineering and CFD

Principal Investigator: Prof. Heinz Pitsch , RWTH Aachen

HPC Platform used: SuperMUC-NG at LRZ

Local Project ID: pn56vo

The recent rise of renewable energy sources is promoting the use of hydrogen as a carbon-free energy carrier. One possibility to harness the energy stored in hydrogen is its usage in thermochemical energy conversion processes such as in gas turbines, industrial burners, or internal combustion engines. However, in contrast to conventional fuels, lean hydrogen/air flames are prone to thermodiffusive instabilities, which can substantially change flame dynamics, heat release rates, and flame speeds. To improve prediction capabilities of Large Eddy Simulations of hydrogen/air flames, detailed data of such flames are needed for model development and validation. However, only rare data of three-dimensional thermodiffusively unstable flames that…

Engineering and CFD

Principal Investigator: Prof. Christian Hasse , TU Darmstadt

HPC Platform used: SuperMUC-NG at LRZ

Local Project ID: pn29so

As a carbon-free fuel, hydrogen has the potential of emerging as the leading energy carrier for next-generation, zero-carbon power generation, and hence has received considerable attention. Hydrogen can offer significant benefits over hydrocarbon fuels, such as wide flammability range, low ignition energy, and high diffusivity. However, the use of hydrogen in gas turbines poses considerable challenges, such as the risk of flashback due to its high flame speed, which adversely affects the performance of hydrogen combustion. Flashback, a problem that occurs in premixed combustors, is the upstream propagation of the flame from the combustor into the premixing tube due to the change in mass flow rate, which could change the combustion process…

Engineering and CFD

Principal Investigator: Karine Truffin , Institut Carnot IFPEN Transports Energie, Energies Nouvelles, Rueil-Malmaison (France)

HPC Platform used: JUWELS of JSC

Local Project ID: pra102/DNS4ICE

Today, car manufacturers rely on CFD tools to design and optimise spark-ignition engines. However, current models of turbulent combustion—which are built based on the assumptions of the flamelet regime—lose their predictivity when used to simulate a highly diluted or ultra-lean combustion involving high turbulent intensities. Yet the combustion in a diluted boosted spark-ignition engine shifts from the flamelet to the thin reaction zone (TRZ) regime. This research project performed direct numerical simulations of premixed C8H18/air statistically flat flame interacting with a turbulent flow field. Results were analysed to develop a combustion model suitable for combustion in the TRZ regime based on the formalism of the coherent flame model.

Engineering and CFD

Principal Investigator: Christian Stemmer, Stefan Hickel , Technische Universität München, Fakultät für Maschinenwesen

HPC Platform used: SuperMUC and SuperMUC-NG of LRZ

Local Project ID: pr45tu

Deceleration of a supersonic flow in a channel by shocks and interaction with the turbulent boundary layer leads to the formation of a complex array of shocks, subsonic and supersonic regions, and recirculation zones. In this project, high-fidelity and well-resolved large-eddy simulations (LES) of such a fully turbulent (Reδ≈105) pseudo-shock system were performed and compared with experimental data. Particular attention is paid to the occurrence of flow instabilities (such as shock motion, shock-boundary layer interaction, and symmetry breaking of the shock system), mixing behaviour in the transonic shear layer, and a comparison with sophisticated RANS turbulence models.

Engineering and CFD

Principal Investigator: Jian Fang , Scientific Computing Department, STFC Daresbury Laboratory, UK

HPC Platform used: Hawk of HLRS

Local Project ID: FlowCDR

Micro-scale directional grooves with spanwise heterogeneity can induce large-scale vortices across the boundary layer, which is of great importance to both theoretical research and industrial applications. The direct numerical simulation approach was adopted in this project to explore flow structure and control mechanism of convergent-divergent (C-D) riblets, as well as the impact of their spacing, wavelength and height. The results show that the C-D riblets produce a well-defined secondary flow motion characterised by a pair of weak large-scale counter-rotating vortices. This roll mode can play a key role in supressing separation when the flow undergoes adverse pressure gradients, but it may also lead to the increase of friction drag.

Engineering and CFD

Principal Investigator: Harald Köstler , Chair for System Simulation, Friedrich-Alexander-Universität Erlangen-Nürnberg

HPC Platform used: SuperMUC and SuperMUC-NG of LRZ

Local Project ID: pr86ma

The open-source software framework waLBerla provides a common basis for stencil codes on structured grids with special focus on computational fluid dynamics with the lattice Boltzmann method. Other codes that build upon the waLBerla core are the particle dynamics module MESA-PD and the finite element framework HYTEG. Various contributors have used waLBerla to simulate a multitude of applications, such as multiphase fluid flows, electrokinetic flows, phase-field methods and fluid-particle interaction phenomena. The software design of waLBerla is specifically aimed to exploit massively parallel computing architectures with highest efficiency.

Engineering and CFD

Principal Investigator: Stefan Platzer , Institute of Helicopter Technology, Technical University of Munich

HPC Platform used: SuperMUC-NG of LRZ

Local Project ID: pn56lu

Rotorcraft are regularly operating in ground effect over moving ship decks or on hillsides. However, only a very limited amount of research has been done to investigate the complex three-dimensional flow fields in these flight conditions and the resulting changes in rotor performance. Therefore, a hovering rotor in non-parallel ground effect was simulated in this project. URANS CFD simulations were made using various turbulence models to gain insight into the three-dimensional flow field, the rotor tip vortex evolution and the velocity distribution in the rotor plane. Best agreement with available experimental data was seen with a Reynolds stress model. Overall, the flow field was most affected close to the rotor hub and on the uphill side.

Engineering and CFD

Principal Investigator: Philip Ströer, Anthony D. Gardner, Kurt Kaufmann , Institute of Aerodynamics and Flow Technology, German Aerospace Center (DLR), Göttingen

HPC Platform used: SuperMUC and SuperMUC-NG of LRZ

Local Project ID: pr83su

Investigations of different approaches to transition modelling on rotors were undertaken, including comparison to experimental data and results of other European CFD codes. For flows at Reynolds numbers below 500,000 the transition transport models predict unphysically large areas of laminar flow compared to the experimental data. A new boundary layer transition model was developed to improve the transition prediction for a wide range of parameters crucial to external aerodynamics. The new model was implemented into the DLR TAU code and works on either structured or unstructured grids. The agreement of the new model with the experimental data is significantly improved compared to the results of the basic transition transport model.

Engineering and CFD

Principal Investigator: Sahin Yigit, Josef Hasslberger, Markus Klein , Numerical Methods in Aerospace Engineering, Bundeswehr University Munich

HPC Platform used: SuperMUC and SuperMUC-NG of LRZ

Local Project ID: pn56di

This project focuses on the modelling and physical understanding of 3D turbulent natural convection of non-Newtonian fluids in enclosures. This topic has wide relevance in engineering applications such as preservation of canned foods, polymer and chemical processing, bio-chemical synthesis, solar and nuclear energy, thermal energy storages. Different aspects of non-Newtonian fluids have been analysed in the course of this work: The behaviour of yield stress fluids in cubical enclosures, 2D and 3D Rayleigh-Bénard convection of power-law fluids in cylindrical and annular enclosures and finally the investigation of Prandtl number (Pr) effects near active walls on the velocity gradient and flow topologies.

Engineering and CFD

Principal Investigator: Michael Manhart , Professorship of Hydromechanics, Technical University of Munich

HPC Platform used: SuperMUC and SuperMUC-NG of LRZ

Local Project ID: pn56ci

In this project the flow in partially-filled pipes is investigated. This flow can be seen as a model flow for rivers and waste-water channels and represents a fundamental flow problem that is not yet fully understood. Nevertheless, there have neither been any high-resolution simulations nor well resolved experiments reported in literature to date for this flow configuration. In this project highly resolved 3D-simulations are performed which help further understanding narrow open-channel and partially-filled pipe flows. The analysis concentrates on the origin of the mean secondary flow and the role of coherent structures as well as on the time-averaged and instantaneous wall shear stress.

Engineering and CFD

Principal Investigator: Metin Muradoglu , Department of Mechanical Engineering, Koc University, Istanbul

HPC Platform used: JUWELS of JSC

Local Project ID: pra112

Researchers of Koc University, Istanbul, performed extensive large-scale direct numerical simulations of turbulent bubbly channel flows to examine combined effects of surfactant and viscoelasticity by using a fully parallelized 3D finite-difference/front-tracking method. The insights achieved shed light for the first time on the intricate interactions of soluble surfactant and viscoelasticity in complex turbulent bubbly flows and reveal their effects on friction drag in channels. The results are expected to guide practitioners in engineering designs such as heat exchangers and pipelines. 

Engineering and CFD

Principal Investigator: Markus Uhlmann , Institute for Hydromechanics, Karlsruhe Institute of Technology (KIT)

HPC Platform used: Hazel Hen and Hawk of HLRS

Local Project ID: GCS-PASC

The quality of surface water typically depends upon a complex interplay between physical, chemical and biological factors which are far from being completely understood. Most practical water quality predictions for rivers or streams rely on various simplifications esp. with regards to the turbulent flow conditions. This project aims at pushing the modeling boundary further by performing massively-parallel computer simulations which resolve all scales of hydrodynamic turbulence in river-like flows, the micro-scale flow around rigid, mobile particles, and the concentration field of suspended bacteria. The data obtained helps quantifying the shortcomings of simpler currently used prediction models and will contribute to their improvement.

Engineering and CFD

Principal Investigator: Klaus Hannemann , Institute of Aerodynamics and Flow Technology, Spacecraft Department. German Aerospace Center (DLR), Göttingen

HPC Platform used: SuperMUC and SuperMUC-NG of LRZ

Local Project ID: pr27ji

Combustion instabilities in rocket thrust chambers pose a serious risk for the development of future launch vehicles as they can’t be predicted reliably by numerical simulations. To better understand the interaction between the flames and acoustic waves inside a combustion chamber, this project numerically investigates the flame response to forced transversal excitation by using Detached-Eddy simulations. In a first step, the eigenmodes of a model combustion chamber are determined from an impulse-response and they are compared to experimental results. We then investigate a specific mode coupling scenario in which the oxygen injector longitudinal eigenmode is adjusted to match the dominant transversal combustion chamber eigenmode.

Engineering and CFD

Principal Investigator: Romuald Skoda , Lehrstuhl für Hydraulische Strömungsmaschinen, Ruhr-Universität Bochum

HPC Platform used: JUWELS of JSC

Local Project ID: chbo46, chbo48

While for the design point operation of centrifugal pumps an essentially steady flow field is present, the flow field gets increasingly unsteady towards off-design operation. Particular pump types as e.g. single-blade or positive displace pumps show a high unsteadiness even in the design point operation. Simulation results for the highly unsteady and turbulent flow in a centrifugal pump are presented. For statistical turbulence models an a-priori averaged turbulence spectrum is assumed, and limitations of these state-of-the-art models are discussed. Since the computational effort of a scale-resolving Large-Eddy-Simulation is tremendous, the potential of scale-adaptive turbulence models is highlighted.

Engineering and CFD

Principal Investigator: Geert Brethouwer , Department of Engineering Mechanics, KTH, Stockholm, Sweden

HPC Platform used: JUWELS of JSC

Local Project ID: PRA108

Flows over the curved surface of wings, cars, turbine blades in gas turbines and impeller blades in pumps have curved streamlines. The influence of streamline curvature on flows, drag and also heat transfer in flows is substantial to large. However, engineering models have difficulties in correctly predicting flows over curved surfaces and our knowledge on streamline curvature influences on flows is still limited. In this project, turbulent flows in moderately to strongly curved channels are studied by highly accurate, large-scale numerical simulations fully resolving the turbulent fluid motions. These give important insights into streamline curvature influences on flows, and produce data that form the basis for better engineering models.

Engineering and CFD

Principal Investigator: Johannes Schemmel , Kirchhoff Institute for Physics, University of Heidelberg (Germany)

HPC Platform used: JUWELS of JSC

Local Project ID: chhd34

Impressive progress has recently been made in machine learning where learning capabilities at (super-)human level can now be produced in non-spiking artificial neural networks. A critical challenge for machine learning is the large number of samples required for training. This project investigated new high-throughput methods across various domains for biologically based spiking neuronal networks. Sub-projects explored tools and learning algorithms to study and enhance learning performance in biological neural networks and to equip variants of data driven models with fast learning capabilities. Applications of these learning techniques in neuromorphic hardware and design for their future application in neurorobotics were also included.

Engineering and CFD

Principal Investigator: Klaus Hannemann , Spacecraft Department, Institute of Aerodynamics and Flow Technology, German Aerospace Center (DLR)

HPC Platform used: SuperMUC and SuperMUC-NG of LRZ

Local Project ID: pr62po

The aerodynamics of generic space launch vehicles, in particular the flow field at the bottom of the vehicle, at transonic conditions are investigated  numerically using hybrid RANS-LES methods. The focus of the project is the investigation of the impact of hot plumes and hot walls on the flow field. It is found that both higher plume velocities and higher wall temperatures shift the reattachment location downstream, leading to a stronger interaction of shear layer and plume. An additional contribution in the pressure spectral content is observed that exhibits a symmetric pressure footprint. The increased wall temperature leads to reduced radial forces on the nozzle structure due to a slower development of turbulent structures.

Engineering and CFD

Principal Investigator: Sylvain Laizet , Imperial College London, United Kingdom

HPC Platform used: Hazel Hen of HLRS

Local Project ID: PRACE4381

The need to reduce the skin-friction drag of aerodynamic vehicles is of paramount importance. Nominally 50% of the total energy consumption of an aircraft or high-speed train is due to skin-friction drag. Reducing skin-friction drag reduces fuel consumption and transport emissions, leading to vast economic savings and wider health and environmental benefits. In this project, wall-normal blowing is combined with a Bayesian Optimisation framework in order to find the optimal parameters to generate net energy savings over a turbulent boundary layer. It is found that wall-normal blowing with amplitudes of less than 1% of the freestream velocity of the boundary layer can generate a drag reduction of up to 80% with up to 5% of energy saving.

Engineering and CFD

Principal Investigator: Manuel Keßler , Institute of Aerodynamics and Gasdynamics, University of Stuttgart

HPC Platform used: Hazeln Hen of HLRS

Local Project ID: GCS-CARo

Helicopters and other rotorcraft like future air taxis generate substantial sound, placing a noise burden on the community. Advanced simulation capabilities developed at IAG over the last decades enable the prediction of aeroacoustics together with aerodynamics and performance, and thus allow an accurate and reliable assessment of different concepts long before first flight. Consequently, this technology serves to identify promising radical configurations initially as well as to further optimize designs decided on at later stages of the development process. Conventional helicopters may benefit from these tools as much as breakthrough layouts in the highly dynamic Urban Air Mobility sector.

Engineering and CFD

Principal Investigator: Panagiotis Stathopoulos , Hermann-Föttinger-Institut, Technische Universität Berlin

HPC Platform used: SuperMUC-NG of LRZ

Local Project ID: pr27bo

Hydrogen-enriched fuels can reduce the CO2 emissions of gas turbines. However, the presence of hydrogen in fuel mixtures can also lead to undesirable phenomena like flashback. Swirling combustors can take advantage of an axial air injection to increase their resistance against flashback. Such an example is the swirl-stabilized presented in experiments at the TU Berlin. The axial momentum ratio between the fuel jets and the air was found to control flashback resistance. This experimental hypothesis motivates the present study where large-eddy simulations of the combustion system are carried out to study the physics behind flashback phenomena in hydrogen gas turbine combustors.

Engineering and CFD

Principal Investigator: Paul Zimmermann , French National Institute for computer science and applied mathematics (INRIA), France

HPC Platform used: JUWELS of JSC

Local Project ID: RSA250

Data sent over the internet relies on public key cryptographical systems to remain secure. A project under leadership of Dr. Paul Zimmermann of the French National Institute for computer science and applied mathematics (INRIA), run on HPC system JUWELS of the Jülich Supercomputing Centre, has been carrying out record computations of integer factorisation and the discrete logarithm problem, the results of which are used as a benchmark for setting the length of the keys needed to keep such systems secure.

Engineering and CFD

Principal Investigator: Xu Chu, Bernhard Weigand , Institut für Thermodynamik der Luft- und Raumfahrt, Universität Stuttgart

HPC Platform used: Hazel Hen and Hawk of HLRS

Local Project ID: PoroDNS

Porous media are everywhere. When Reynolds numbers in pores are large, the unsteady inertial effects become important giving rise to the onset of turbulence, for instance in packed bed catalysis, gas turbine cooling, and pebble-bed high-temperature nuclear reactors. Access to detailed flow measurements is very challenging due to the inherent space constraints of the porous media. Therefore, a research group of the Institute of Aerospace Thermodynamics (ITLR) at University of Stuttgart uses high-fidelity direct numerical simulation (DNS) to investigate the physics of fluids inside porous media which serves for industrial 3D-printed porous media design.

Engineering and CFD

Principal Investigator: Feichi Zhang , Engler-Bunte-Institute, Karlsruhe Institute of Technology

HPC Platform used: Hazel Hen and Hawk of HLRS

Local Project ID: DNSbomb

Combustion remains the most important process for power generation and more research is needed to reduce future pollutant emissions. However, combustion is governed by thermo-chemical processes that interact over a wide range of length and time scales. Detailed simulations are of high interest to gain more information about flames. Two examples of large-scale simulations of challenging flame setups are given: The thermo-diffusive instabilities of hydrogen flames as well as the interplay between turbulent flow and flames. A special method for investigating the local dynamics of flames, called flame particle tracking, has been implemented specifically for large parallel clusters for high performance computing to further evaluate these cases.

Engineering and CFD

Principal Investigator: Christian Hasse , Simulation of reactive Thermo-Fluid Systems, Technical University of Darmstadt

HPC Platform used: SuperMUC and SuperMUC-NG of LRZ

Local Project ID: pr74xi

Using a canonical jet in cross flow (JICF) flame configuration, researchers of TU Darmstadt performed a high-resolution DNS study concerning differential diffusion effects and mixing characteristics during hydrogen combustion. The investigations in the hydrogen JICF configurations were twofold. First, a detailed analysis of the DNS data was to yield a fundamental understanding of mixing characteristics in the JICF configuration and differential diffusion effects. Second, commonly applied tabulated chemistry approaches and their capability of predicting differential diffusion were to be validated against the DNS data. The latter, which is of highly practical interest for a related project, was the final target of this project.

Engineering and CFD

Principal Investigator: Dr. Manuel Keßler , Institute of Aerodynamics and Gas Dynamics, University of Stuttgart

HPC Platform used: Hazel Hen and Hawk of HLRS

Local Project ID: GCSHELISIM

The helicopters & aeroacoustics group of the Institute of Aerodynamics and Gas Dynamics at the University of Stuttgart continues to develop their well-established and validated rotorcraft simulation framework. Vibration prediction and noise reduction are currently the focus of research, and progress into manoeuvre flight situations is on the way. For two decades, high-performance computing leverged within the HELISIM project has enabled improvements for conventional helicopters as much as for the upcoming eVTOLs, commonly known as air taxis, in terms of performance, comfort, and efficiency. Community acceptance will be fostered via noise reduction and safety enhancements, made possible by this research project.

Engineering and CFD

Principal Investigator: Jörg Schumacher , Technische Universität Ilmenau

HPC Platform used: SuperMUC and SuperMUC-NG of LRZ

Local Project ID: pr62se, pn68ni

Turbulent convection is one essential process to transport heat in fluid flows. In many of the astrophysical or technological applications of convection the working fluid is characterized by a very low dimensionless Prandtl number which relates the kinematic viscosity of the fluid to its temperature diffusivity. Two important cases are turbulent convection in the Sun and turbulent heat transfer in the cooling blankets of nuclear fusion reactors. Massively parallel simulations of the simplest setting of a turbulent convection flow, Rayleigh-Bénard convection in a layer or a straight duct that is uniformly heated from below and cooled from above, help to understand the basic heat transfer mechanisms that these applications have in common.

Engineering and CFD

Principal Investigator: Matthias Meinke , Chair of Fluid Mechanics and Institute of Aerodynamics, RWTH Aachen University

HPC Platform used: Hazel Hen and Hawk (HLRS), JUQUEEN (JSC)

Local Project ID: GCS-Aflo (HLRS), chac32 (JSC)

A new active surface actuation technique to reduce the friction drag of turbulent boundary layers is applied to the flow around an aircraft wing section. Through the interaction of the transversal traveling surface wave with the turbulent flow structures, the skin-friction on the surface can be considerably reduced. Highly-resolved large-eddy simulations are conducted to investigate the influence of the surface actuation technique on the turbulent flow field around an airfoil at subsonic flow conditions. The active technique, which previously was only tested in generic scenarios, achieves a considerable decrease of the airfoil drag.

Engineering and CFD

Principal Investigator: Ulrich Rist, Markus Kloker, Christoph Wenzel , Institute of Aerodynamics and Gas Dynamics, University of Stuttgart

HPC Platform used: Hazel Hen and Hawk of HLRS

Local Project ID: GCS-Lamt

This project explores laminar-turbulent transition, turbulence, and flow control in boundary layers at various flow speeds from the subsonic to the hypersonic regime. The physical problems under investigation deal with prediction of laminar-turbulent transition on airfoils for aircraft, prediction of critical roughness heights in laminar boundary layers, turbulent drag reduction, the origins of turbulent superstructures in turbulent flows, the use of roughness patterns for flow control, effusion cooling in laminar and turbulent supersonic boundary-layer flow, DNS of disturbance receptivity on a swept wing at high Reynolds numbers, and plasma actuator design for active control of disturbances in a swept-wing flow.

Engineering and CFD

Principal Investigator: Christian Bauer , Institute of Aerodynamics and Flow Technology, German Aerospace Center (DLR)

HPC Platform used: SuperMUC and SuperMUC-NG of LRZ

Local Project ID: pr62zu

A large amount of the energy needed to push fluids through pipes worldwide is dissipated by viscous turbulence in the vicinity of solid walls. Therefore the study of wall-bounded turbulent flows is not only of theoretical interest but also of practical importance for many engineering applications. In wall-bounded turbulence the energy of the turbulent fluctuations is distributed among different scales. The largest energetic scales are denoted as superstructures or very-large-scale motions (VLSMs). In our project we carry out direct numerical simulations (DNSs) of turbulent pipe flow aiming at the understanding of the energy exchange between VLSMs and the small-scale coherent.

Engineering and CFD

Principal Investigator: Barbara Wohlmuth , Lehrstuhl für Numerische Mathematik, Technische Universität München

HPC Platform used: SuperMUC and SuperMUC-NG of LRZ

Local Project ID: pr74ne

Large scale simulations are particularly valuable and important for a better understanding of coupled multi physics problems describing a large class of physical phenomena. This research project focuses on the development of new numerical methods for efficiently solving coupled non-linear and time-dependent fluid flow problems on a large scale. In particular, two applications are considered. Namely, the Navier–Stokes equations coupled to a transport equation describing diluted polymers and geodynamical model problems which involve non-linearities in the viscosity. The goal is to develop new methods for solving these problems, evaluating their performance and scalability, and to perform simulations based on these new methods.

Engineering and CFD

Principal Investigator: Andreas Goerttler, Anthony Gardner , Institute for Aerodynamics and Flow Technology, German Aerospace Center (DLR), Göttingen

HPC Platform used: SuperMUC and SuperMUC-NG of LRZ

Local Project ID: pr53fi

Using DLR’s finite-volume solver TAU, researchers of the Institute for Aerodynamics and Flow Technology at DLR Göttingen numerically investigated the vortex system of four rotating and pitching DSA-9A blades. The computations were validated against experimental data gathered using particle image velocimetry (PIV) carried out at the rotor test facility in Göttingen. Algorithms deriving the vortex position, swirl velocity, circulation and core radius were implemented. Hover-like conditions with a fixed blade pitch were analyzed giving a good picture of the static vortex system. These results are used to understand the vortex development for the unsteady pitching conditions, which can be described as a superposition of static vortex states.

Engineering and CFD

Principal Investigator: Xiangyu Hu , Chair of Aerodynamics and Fluid Mechanics, Technische Universität München

HPC Platform used: SuperMUC and SuperMUC-NG of LRZ

Local Project ID: pr53vu

As a Lagrangian method, Smoothed Particle Hydrodynamics (SPH) has been explored and demonstrated for a wide range of applications. Several open-source frameworks exist for the large-scale parallel simulation of particle-based methods in which the resolution of simulation is fixed. Some preliminary work has also been published to tackle the difficulties encountered in extending codes with adaptive-resolution capability. However, the support for fully parallelized adaptive-resolution in distributed systems is generally still limited in the aforementioned codes. This research project focuses on an alternative approach by introducing a new multi-resolution parallel framework employing several algorithms from previous work.

Engineering and CFD

Principal Investigator: Franco Magagnato , Institute of Fluid Mechanics, Karlsruhe Institute of Technology

HPC Platform used: Hazel Hen and Hawk of HLRS

Local Project ID: Imp_DNS

The heat transfer in the stagnation region of an impinging jet at given jet to distance ratio, Re-number and Temperature ratio also depend on the turbulent inflow characteristics. Using Direct Numerical Simulations, the Nusselt-number distribution as well as the turbulent statistics close to the heated wall have been investigated. At first a calculation has been done comparing the results with published DNS and experiments from Dairay et al. (2015). Since in their paper not all necessary turbulence values were given, the missing values (e.g. turbulent length scale) had to be adjusted in order to fit their results. A good agreement has been found of our calculations with their DNS and experiments.

Engineering and CFD

Principal Investigator: Claus-Dieter Munz , Institute of Aerodynamics and Gas Dynamics, University of Stuttgart

HPC Platform used: Hazel Hen and Hawk of HLRS

Local Project ID: hpcmphas

In order to simulate compressible multi-phase flows at extreme ambient conditions, researchers from the Institute of Aerodynamics and Gas Dynamics have developed a multi-phase flow solver based on the discontinuous Galerkin spectral element method in conjunction with an efficient tabulation technique for highly accurate equations of state. The aim of this development is the simulation of phase transition, droplet dynamics and large-scale multi-component phenomena at pressures and temperatures near the critical point. Simulations of liquid fuel injections and shock-drop interactions have been performed on the HPC systems installed at the High-Performance Computing Center Stuttgart (HLRS).

Engineering and CFD

Principal Investigator: Manuel Keßler , Institute of Aerodynamics and Gas Dynamics, University of Stuttgart

HPC Platform used: Hazel Hen and Hawk of HLRS

Local Project ID: DGDES

The aerodynamic flow field around helicopters is challenging to simulate due to complex configurations in relative motion. In an effort to evolve computational fluid dynamics (CFD) technology to new levels of accuracy, reliability, and parallelization efficiency, the helicopter & aeroacoustics group at the IAG of University of Stuttgart employs advanced, high-order Discontinuous Galerkin (DG) methods to help solve difficult rotorcraft-based engineering applications. Complex geometries, curved surfaces, relative motion with elaborate kinematics, and fluid-structure coupling to blade dynamics call for sophisticated techniques within the simulation tool chain to account for all important physical phenomena relevant to the field of study.

Engineering and CFD

Principal Investigator: Harald Klimach , Simulation Techniques and Scientific Computing, University of Siegen

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr62cu

This project looked into various strategies to couple domains of distinct physical and numerical properties to tackle direct aero-acoustic simulations. A turbulent flow around an airfoil and the emitted sound waves in a large area of interest was simulated. Different physical effects can be observed in spatially separated domains and the appropriate equation systems are solved in each one using the best fitting numerical discretization. The main focus of the project was the evaluation of different coupling methods to enable this partitioned simulation on massively parallel systems.

Engineering and CFD

Principal Investigator: Andrea Beck(1), Claus-Dieter Munz(1), Christian Rohde(2) , (1) Institute of Aerodynamics and Gas Dynamics, University of Stuttgart, (2) Institute of Applied Analysis and Numerical Simulation, University of Stuttgart

HPC Platform used: Hazel Hen of HLRS

Local Project ID: SEAL

In order to quantify the uncertainty due to stochastic input in computer fluid dynamic simulations, researchers from the Institute of Aerodynamics and Gas Dynamics developed an Uncertainty Quantification framework and applied it to direct noise computations of aeroacoustic cavity flows. Simulations have been performed with the discontinuous Galerkin spectral element method on HPC system Hazel Hen at the High Performance Computing Center Stuttgart (HLRS). The aim of this investigation is to gain insight into the sensitivity of uncertain input with respect to the acoustic results and to get a reliable comparison between numerical and experimental results.

Engineering and CFD

Principal Investigator: Jordan A. Denev , Steinbuch Centre for Computing, Karlsruhe Institute of Technology

HPC Platform used: JUWELS of JSC

Local Project ID: chka20

The simulation of turbulent, partially premixed flames constitutes a challenge due to the complex interplay of the mixing process of fuel and oxidizer, chemical reactions and turbulent flow. Therefore, a detailed numerical simulation of an experimentally investigated flame of laboratory scale has been performed, which allows to study these fundamental interactions in great detail. The results have been compiled into a database which aids the improvement of future combustion simulations. The simulation has been performed with an in-house solver based on OpenFOAM, which includes several performance optimizations to maximize the hardware utilization on supercomputers.

Engineering and CFD

Principal Investigator: Wolfgang Polifke , Department of Mechanical Engineering, Technische Universität München

HPC Platform used: SuperMUC, Phase I and II

Local Project ID: pr94yu

Combustion noise is an undesirable, but unavoidable by-product of turbulent combustion in, e.g., stationary gas turbines or aeronautical engines. This project combines Large Eddy Simulation (LES) of turbulent, reacting flow with advanced System Identification (SI) – a form of supervised machine learning –  to infer reduced-order models of combustion noise. Models for the source of noise on the one hand, and the flame dynamic response to acoustic perturbations on the other, are estimated to make possible the flexible and computationally efficient prediction of combustion noise across a wide variety of combustor configurations.

Engineering and CFD

Principal Investigator: Oriol Lehmkuhl , Barcelona Supercomputing Center

HPC Platform used: SuperMUC of LRZ

Local Project ID: pn69fa

New wind harnessing generators that gather energy through a phenomenon known as vortex-induced vibrations could represent a new frontier for renewable energy. Researchers of the Barcelona Supercomputing Centre have been using high-performance computing system SuperMUC of the Leibniz Supercoputing Centre to help advance this technology.

Engineering and CFD

Principal Investigator: Jörg Schumacher , Institute of Thermodynamics and Fluid Mechanics, TU Ilmenau (Germany)

HPC Platform used: JUWELS of JSC

Local Project ID: chil12

Recent direct numerical simulations in closed slender Rayleigh-Bénard convection cells advanced to Rayleigh numbers of Ra = 1015 which were never obtained before and reveal a classical turbulent transport law for the heat transfer from the bottom to the top of the cell which is based on the concept of marginally stable boundary layers. Our simulations were able to resolve the complex dynamics inside the thin boundary layers at the top and bottom plates of the convection cell and to determine a steady increase of the turbulent fluctuations without an abrupt transition near the wall for a range of 8 orders of magnitude in Rayleigh number.

Engineering and CFD

Principal Investigator: Theresa Trummler, Steffen Schmidt , Chair of Aerodynamics and Fluid Mechanics, Technische Universität München

HPC Platform used: SuperMUC, Phase I and II

Local Project ID: pr86ta

Recent developments in direct injection systems aim at increasing the rail pressures to more than 3000 bar for Diesel and 1000 bar for gasoline, to enhance liquid break-up and mixing which in turn improves combustion and reduces emissions. Higher flow accelerations, however, imply thermo-hydrodynamic effects, e.g. cavitation, which occurs when the pressure locally drops below saturation conditions and the liquid vaporizes. The subsequent collapse of such vapor structures causes the emission of strong shock-waves leading to material erosion. But cavitation can also be beneficial by promoting primary jet break-up, thus the ability to predict cavitation and cavitation erosion during the early stages of design of fuel injectors is desirable.

Engineering and CFD

Principal Investigator: Frank Holzäpfel , German Aerospace Center (DLR), Institute of Atmospheric Physics

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr63zi

Aircraft wake vortices pose a potential threat to following aircraft. Highly resolving numerical simulations provide valuable in-sights in the physics of wake vortex behaviour during different flight phases and under various environmental conditions. Hybrid simulation techniques introduce the flowfield around detailed aircraft geometries into an atmospheric environment that controls the vortical aircraft wake until its decay. The vision of virtual flight in a realistic environment is addressed by the two-way coupling of two separate flow solvers. To mitigate the risk of wake encounters and thereby to improve runway capacity, so-called plate lines have been developed and tested at Vienna airport.

Engineering and CFD

Principal Investigator: Andrea Beck, Claus-Dieter Munz , Institute of Aerodynamics and Gasdynamics, University of Stuttgart

HPC Platform used: Hazel Hen of HLRS

Local Project ID: HPCDG

In order to analyse the complex flow in rotating turbomachinery components, researchers from the Institute for Aerodynamics and Gas Dynamics performed high fidelity, large-scale turbulent flow computations of stator-rotor interactions using the discontinuous Galerkin spectral element method on the HPC system Hazel Hen at the High Performance Computing Center Stuttgart (HLRS). The aim of this investigation is to gain insight into the intricate time-dependent behaviour of these flows and to inform future design improvements.

Engineering and CFD

Principal Investigator: Thomas Indinger and Lu Miao , Chair of Aerodynamics and Fluid Mechanics, Technical University of Munich

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr42re

With constantly growing fuel prices and toughening of environmental legislation, the vehicle industry is struggling to reduce fuel consumption and decrease emission levels for the new and existing vehicles. One way to achieve this goal is to improve aerodynamic performance by decreasing aerodynamic resistance. Leveraging HPC resources, researchers of the Technical University of Munich conducted a wide range of studies with the aim to improve modeling techniques, develop a profound understanding for flow phenomena, and optimize vehicle shapes.

Engineering and CFD

Principal Investigator: Theresa Trummler, Steffen Schmidt , Institute of Aerodynamics and Fluid Mechanics, Technische Universität München

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr92ho

Recently, European legislative bodies have imposed significant restrictions on the emission level of Diesel injections systems, thus challenging car manufacturers and suppliers to reduce pollution. Improvement of the combustion process and spray quality has become a main objective in fulfilling those policies, which is mainly achieved by increasing injection pressures. Therefore, understanding internal nozzle flows has become a key aspect in designing efficient and durable Diesel injection systems. Since to this date quantitative experimental investigations are challenging, researchers use HPC technologies and computational fluid dynamics to complement experimental findings by providing additional information about the flow topology.

Engineering and CFD

Principal Investigator: Christian Hasse , Simulation of Reactive Thermo-Fluid Systems, Technische Universität Darmstadt

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr74li

A series of highly resolved direct numerical simulations (DNSs) of temporally evolving turbulent non-premixed jet flames was conducted on the SuperMUC of LRZ. Two promising approaches were used to analyze the databases. The first approach, on-the-fly tracking flamelet structure, helps to understand the effects of neglecting tangential diffusion (TD) on the performance of classical flamelet models. The second approach - dissipation elements – helps to develop possible closure strategies for including flame-tangential effects in the flamelet models. Moreover, TD was used as an important performance indicator to assess tabulation strategies, differential diffusion effects, and Soret effects in turbulent non-premixed combustion.

Engineering and CFD

Principal Investigator: Heinz Pitsch , Institute for Combustion Technology, RWTH Aachen University

HPC Platform used: JUWELS of JSC

Local Project ID: cjhpc09

A high fidelity, high Reynolds number direct numerical simulation (DNS) of a planar temporally evolving non-premixed jet flame was performed on the new supercomputer JUWELS of JSC. The DNS enabled the detailed investigation of combustion conditions with a high level of scale interaction between combustion chemistry and turbulence. Furthermore, the simulation was instrumental in understanding how the structure of scalar fields is affected by heat release in non-premixed flames. The insights gained from the DNS are instrumental in the development of new combustion models with the goal of improving the accuracy of simulations of real-world engineering applications.

Engineering and CFD

Principal Investigator: Jörn Sesterhenn , Institut für Strömungsmechanik und Technische Akustik, Technische Universität Berlin

HPC Platform used: Hazel Hen of HLRS

Local Project ID: JetCool

An effective cooling of the gas turbine components subject to high thermal stresses is vital for the success of new engine and combustion concepts aiming at achieving further improvements in the energy conversion efficiency of the overall machine. The use of pulsating impinging jets - which enlarge vortex structures naturally occurring in the impinging jet flow when no pulsation is enforced - is a promising approach to develop a substantially more performant cooling system. To gain a deeper understanding of how the vortex system behaves under realistic conditions, researchers performed a DNS of a non-pulsating impinging jet flow with fully turbulent inflow conditions and compared its results with a reference case with a laminar inflow.

Engineering and CFD

Principal Investigator: Wolfgang Schröder , Institute of Aerodynamics, RWTH Aachen University (Germany)

HPC Platform used: JUQUEEN of JSC

Local Project ID: PRA094

Researchers of the Institute of Aerodynamics at RWTH Aachen University used large-eddy simulation and computational aeroacoustics methods to analyze noise sources in turbulent flames and the interaction of the resulting acoustic waves with the flame and the turbulent flow field. To achieve accurate results of the flow and the acoustic field highly resolved large-scale simulations with several hundred million mesh points are necessary. The simulation results have given new insights into fundamental sound-generation mechanisms and their phase-relationship that are important for the prediction and control of thermoacoustic instabilities, and ultimately, the development of more efficient and gas turbines with lower pollutant emissions.

Engineering and CFD

Principal Investigator: Timo Krappel , Institute of Fluid Mechanics and Hydraulic Machinery, University of Stuttgart

HPC Platform used: Hornet and Hazel Hen of HLRS

Local Project ID: LESFT

In recent years, hydroelectric power plants have received increased attention for the role they play in integrating volatile renewable energies that contribute to stabilizing the electrical grid. One major issue, though, is rooted in running turbines under conditions they were not originally designed for, leading to undesirable flow phenomena. With the standard modeling approaches that are typically used in industry simulations of hydroelectric turbines, simulation accuracy in scenarios where the turbine is used off-design is rather poor. The goal of this project is to increase simulation accuracy by the selection of suitable modeling approaches and the use of a fine mesh resolution, which is only possible by the use of supercomputers.

Engineering and CFD

Principal Investigator: Luis Cifuentes , Chair of Fluid Dynamics, University of Duisburg-Essen

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr53fa

A GCS large-scale project under leadership of Dr.-Ing. Cifuentes of the University of Duisburg-Essen aims at understanding the physics of entrainment in turbulent premixed flames. This research characterizes the entrainment processes through the study and comparison of the flame front and the enstrophy interface. This is an essential issue in reactive turbulent flows, because a better understanding of the dynamics of the flame front and the enstrophy interface leads to better predictions of flame instabilities and scalar structures.

Engineering and CFD

Principal Investigator: Neil Sandham , Faculty of Engineering and Physical Sciences, University of Southampton (U. K.)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: PP17174149

Shock-related buffeting is a phenomenon that occurs when air passes over the wing of an aeroplane under extreme conditions and can have profound consequences for how wings are engineered and their durability. Leveraging the computing capacities of HPC system Hazel Hen, researchers at the University of Southampton have been investigating this phenomenon using direct numerical simulations.

Engineering and CFD

Principal Investigator: Qiaoyan Ye and Bo Shen , Fraunhofer Institute for Manufacturing Engineering and Automation, Stuttgart

HPC Platform used: Hazel Hen of HLRS

Local Project ID: PbusRobe

Spray painting is the most common application technique in coating technology. Typical atomizers used in spray coating industries are such as High-speed rotary bell and spray guns with compressed air. High-speed rotary bell atomizers provide an excellent paint film quality as well as high transfer efficiencies (approx. 90%) due to electrostatic support. Small and medium-sized enterprises continue, however, to use compressed air atomizers, although they no longer meet today's requirements from an economic and environmental point of view. It is very important to understand the atomization mechanisms of these two kinds of atomizers, in order to improve the paint quality, to reduce the overspray and to optimize the coating process.

Engineering and CFD

Principal Investigator: Detlef Lohse , Max-Planck-Institut für Dynamik und Selbstorganisation, Göttingen (Germany), and Max Planck Center Twente for Complex Fluid Dynamics and Physics of Fluids Group, University of Twente (The Netherlands)

HPC Platform used: JUWELS of JSC

Local Project ID: PRA099

Many wall-bounded flows in nature and technology are affected by the surface roughness of the wall. In some cases, this has adverse effects, e.g. drag increase leading to higher fuel costs; in others, it is beneficial for mixing enhancement or transfer properties. Computationally, it is notoriously difficult to simulate these flows because of the vast separation of scales in highly turbulent flows and the challenges involved in handling complex geometries. The studies are carried out in two paradigmatic and complementary systems in turbulence research, Taylor-Couette and Rayleigh-Bénard flow.

Engineering and CFD

Principal Investigator: Martin Thomas Horsch, Maximilian Kohns , Laboratory of Engineering Thermodynamics, Technische Universität Kaiserslautern

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr48te

Molecular modelling and simulation is an established method for describing and predicting thermodynamic properties of fluids. This project examines interfacial properties of fluids, their contact with solid materials, interfacial fluctuations and finite-size effects, linear transport coefficients in the bulk and at interfaces and surfaces as well as transport processes near and far from equilibrium. These phenomena are investigated by massively-parallel molecular dynamics simulation based on quantitatively reliable classical-mechanical force fields.

Engineering and CFD

Principal Investigator: Manfred Krafczyk , Institute for Computational Modeling in Civil Engineering of the Technische Universität Braunschweig (Germany)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr53yu

Flow noise during takeoff and landing of commercial aircraft can be substantially reduced by the use of porous surface layers in suitable sections of the airfoil. However, porosity and roughness of surfaces tend to have an adverse effect on the boundary layer and thus on the lift of wings. This motivates the need to be able to predict the aerodynamic effects of porous segments of the wing surface by numerical methods. Due to the inherent requirements of resolving both the turbulence on the scale of an airfoil and the flow inside the pore-scale resolved porous medium, the simulations run on SuperMUC required more than a billion grid nodes on a locally refined three-dimensional mesh.

Engineering and CFD

Principal Investigator: Univ.-Prof. Dr.-Ing. habil. Michael Breuer , Department of Fluid Mechanics, Helmut-Schmidt-University, Hamburg (Germany)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr53ne

The interaction between fluids and structures (fluid structure interaction/FSI) is a topic of interest in many science fields. In addition to experimental investigations, numerical simulations have become a valuable tool to foresee complex flow phenomena such as vortex shedding, transition and separation or critical stresses in the structure exposed to the flow. In civil engineering, e.g., structures are exposed to strong variations of the wind, particularly wind gusts, and such high loads can ultimately lead to a complete destruction of the structure. Scientists are leveraging HPC technologies in order to model wind gusts and to comprehend their impact on the FSI phenomenon.

Engineering and CFD

Principal Investigator: Detlef Lohse (1, 2), Richard Stevens (2) , (1) Max-Planck-Institut für Dynamik und Selbstorganisation, Göttingen (Germany), (2) Max Planck Center Twente for Complex Fluid Dynamics and Physics of Fluids Group, University of Twente (The Netherlands)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr74sa

Turbulent thermal convection plays an essential role in a wide range of natural and industrial settings, from astrophysical and geophysical flows to process engineering. While heat transfer in industrial applications takes place in confined systems, the aspect ratio in many natural instances of convection is huge. Interestingly, flow organization on enormous scales is observed in, for example, oceanic and atmospheric convection. However, our physical understanding of the formation of turbulent superstructures is limited. In this project, we analyze the flow organization within turbulent superstructures and show that their size increases when the thermal driving is increased.

Engineering and CFD

Principal Investigator: Nikolaus A. Adams , Institute of Aerodynamics and Fluid Mechanics, Technische Universität München

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr45wa

The efficient mixing of fuel and oxidizer is essential in modern combustion engines. Especially in supersonic combustion the rapid mixing of fuel and oxidizer is of crucial importance as the detention time of the fuel-oxidizer mixture in the combustion chamber is only a few milliseconds. The shock-induced Richtmyer-Meshkov instability (RMI) promotes mixing and thus has the potential to increase the burning efficiency of supersonic combustion engines. To study the interaction between RMI and shock-induced reaction waves, which affects the flow field evolution und the mixing significantly, researchers leveraged HPC system SuperMUC to run 3D simulations of reacting shock-bubble interaction.

Engineering and CFD

Principal Investigator: Prof. Jörg Schumacher , Technische Universität Ilmenau (Germany)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr62se

Turbulent convection flows in nature and technology often show prominent and nearly regular patterns on their largest scales which we term turbulent superstructures. Their appearance challenges the classical picture of turbulence in which a turbulent flow is considered as a tangle of chaotically moving vortices. Examples for superstructures in nature are cloud streets in the atmosphere or the granulation at the surface of the Sun. In several applications, this structure formation is additionally affected by magnetic fields. Our understanding of the origin of turbulent superstructures and their role for the turbulent transport is presently still incomplete and will be improved by direct numerical simulations of turbulent convection.

Engineering and CFD

Principal Investigator: Wolfgang Schröder , Institute of Aerodynamics, RWTH Aachen University (Germany)

HPC Platform used: Hazel Hen of HLRS and JUQUEEN of JSC

Local Project ID: GCS-SOPF (HLRS) and hac31 (JSC)

Researchers of the Institute of Aerodynamics (AIA) at RWTH Aachen University conducted large-scale benchmark simulations on supercomputer Hazel Hen of the High-Performance Computing Center Stuttgart to analyze the interaction of non-spherical particles with turbulent flows. These simulations provide a unique data base for the development of simple models which can be applied to study complex engineering problems. Such models are required in a larger research framework to improve the efficiency of pulverized coal and biomass combustion to significantly reduce the CO2 emissions.

Engineering and CFD

Principal Investigator: Andreas Kempf , Institute for Combustion and Gas Dynamics, Chair of Fluid Dynamics, University of Duisburg-Essen

HPC Platform used: Hazel Hen of HLRS

Local Project ID: GCS-JFLA

Transient mixing and ignition play a significant role in many systems, where combustion efficiency and emissions are controlled by ignition and mixing dynamics. In the present work, high fidelity simulations of a pulsed fuel injection system are carried out using state of the art numerical tools and high-performance computing. The results contain all parameters that affect ignition dynamics and are mined and analyzed. The physics of transient reactive turbulent jets are thus identified and presented that partners in industry and academia can improve their understanding of the process and work on the design of better combustion devices.

Engineering and CFD

Principal Investigator: Andreas Kempf , Institute for Combustion and Gas Dynamics, Chair of Fluid Dynamics, University of Duisburg-Essen

HPC Platform used: Hazel Hen of HLRS

Local Project ID: GCS-snef

Shock-tube experiments are a classical technique to provide data for reaction mechanisms and thus help to reduce emissions and increase the efficiency of combustion processes. A shock-tube experiment at critical conditions (low temperature), where the ignition occurs far away from the end wall, is simulated. Understanding the mechanism that leads to such a remote ignition is crucial to improve the quality of future experiments.

Engineering and CFD

Principal Investigator: Heinz Pitsch , Institute for Combustion Technology, RWTH Aachen University, Germany

HPC Platform used: Hazel Hen of HLRS

Local Project ID: GCS-mres

In order to support sustainable powertrain concepts, synthetic fuels show significant potential to be a promising solution for future mobility. It was found that the formation of soot and CO2 emissions during the energy transformation process of synthetic fuels can be reduced compared to conventional fuels and that sustainable fuel production pathways exists. Simulations of these multiphase, reactive systems are needed to fully unlock the potential of new powertrain concepts. Due to the large separation of scales, these simulations are only possible with current supercomputers.

Engineering and CFD

Principal Investigator: Dan S. Henningson , KTH Royal Institute of Technology, Stockholm (Sweden)

HPC Platform used: Hazel Hen of HLRS and Beskow of PDC KTH

Local Project ID: PP16163965

Recently there has been a large push in the aircraft industry to reduce its carbon footprint. Laminar flow control and Natural Laminar Flow (NLF) wing design have been proposed as one of the main options for reducing the drag on the airplane and hence its fuel consumption. One of the important aspects of aircraft design concerns dynamic stability and an understanding of the unsteady behavior of NLF airfoils is important for predicting the stability characteristics of the aircraft. Recent experimental studies on NLF airfoils have shown that their dynamic behavior differs from that of turbulent airfoils and that classical linearized models for unsteady airfoils fail to predict the unsteady behavior of NLF airfoils. Most notably, NLF airfoils…

Engineering and CFD

Principal Investigator: Thorsten Lutz , Institute of Aerodynamics and Gas Dynamics (IAG), University of Stuttgart (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: WEAloads

As part of the WindForS project WINSENT two wind turbines and four met masts will be installed in the Swabian Alps in Southern Germany for research proposes. The results of highly resolved numerical simulations of this wind energy test site located in complex terrain are shown. By means of Delayed Detached Eddy Simulations (DDES) the turbulent flow above a forested steep slope is analyzed in order to evaluate the inflow conditions of the planned wind turbine in detail. The complex inflow conditions and production of turbulence due to the shape of the topography and the vegetation are evaluated. The intention of using supercomputers for these applications is to analyze the local atmospheric flow field in as much detail as possible.

Engineering and CFD

Principal Investigator: Eckart Laurien , Institute of Nuclear Technology and Energy Systems (IKE), University of Stuttgart (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: TurboCon3

The accident management in a generic nuclear power plant containment with a convection flow of high-temparature gases is simulated. An activated spray mixes the turbulent flow and inhibits the formation of a possibly explosive upper region filled with hydrogen. Condensation of the steam is promoted and the maximum pressure, which may also endanger the containment integrity, is limited.

Engineering and CFD

Principal Investigator: Olga Shishkina , Max Planck Institute for Dynamics and Self-Organization, Göttingen (Germany)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr84pu, pr92jo

Turbulent thermal convection is ubiquitous in nature and technical applications. Inclined convection, where a fluid is confined between two differently heated parallel surfaces, which are inclined with respect to gravity, is one of the main model systems to study the physics of turbulent thermal convection. In this project, we focus on the investigation of the interaction between shear and buoyancy and want to know, how they influence the development of the flow superstructures and contribute to the mean heat transport enhancement in the system.

Engineering and CFD

Principal Investigator: Jonas Wack , Institute of Fluid Mechanics and Hydraulic Machinery, University of Stuttgart (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: HYPERBOL

In the last decades, hydro power plants have experienced a continual extension of the operating range in order to integrate other renewable energy sources into the electrical grid. When operated at off-design conditions, the turbine experiences cavitation which may reduce the power output and can cause severe damage in the machine. Cavitation simulations are necessary to investigate phenomena like the full load instability. The goal of this project is to understand the physical mechanisms that result in an instability at off-design conditions to identify measures that can avoid the occurrence of instability.

Engineering and CFD

Principal Investigator: Koen Hillewaert, Ariane Frère, Michel Rasquin , Cenaero Research Center (Belgium)

HPC Platform used: JUQUEEN of JSC

Local Project ID: PRA096

Wind turbine and aircraft design relies on numerical simulation. Current aerodynamic models represent turbulence not directly but model its averaged impact. Such models are only reliable near the design point and require vast experience of the design engineer. Industry wants therefore to enable more accurate methods, such as wall-modeled Large-Eddy Simulation (wmLES) which represents turbulent flow structures directly. R2Wall provides a high-resolution simulation of the NACA4412 airfoil as reference data for the development of wall-models for LES and turbulence models in general. This project has enabled the definition of guidelines for future computations, and the calibration of wall-models.

Engineering and CFD

Principal Investigator: Luca Brandt , Department of Mechanics, KTH, Royal Institute of Technology (Sweden)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: PP16153682

The focus of this project is the direct numerical simulation (DNS) of an evaporating spray in a turbulent channel flow. The complexity of the phenomenon lies in the nonlinear interaction of phase change thermodynamics and turbulent transport mechanisms at a multitude of scales. The recent availability of larger supercomputing power, together with our novel technique to treat efficiently the interface resolved phase change, enables us to perform the first DNS of more than 14k droplets evaporating in turbulent flow, with full coupling of momentum, heat and mass transfer, both intra- and inter-phase.

Engineering and CFD

Principal Investigator: Julien Bodart , ISAE-SUPAERO, Université de Toulouse (France)

HPC Platform used: JUQUEEN of JSC

Local Project ID: PRA097

In this study, researchers in fluid mechanics at ISAE-SUPAERO investigate possible control of shock boundary layer interaction, a well known flow phenomenon occuring on high speed supersonic devices. In particular, low frequency modes have a significant impact on the device load. High fidelity simulations of turbulent flows are performed to understand the modifications of the flow field induced by the microramp vortex generators located upstream the interaction.

Engineering and CFD

Principal Investigator: Markus Klein and Sebastian Ketterl , Institute of Mathematics and Applied Computing, Bundeswehr University Munich

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr48no

Primary goal of this project, run on HPC system SuperMUC of LRZ, was the establishing of a direct numerical simulation (DNS) data base of primary breakup of a liquid jet injected into stagnant air. Due to the wide range of time and length scales the development of a predictive large eddy simulation (LES) framework is highly desirable. However, the multiscale nature of atomization is challenging, as the presence of the phase interface causes additional subgrid scale terms to appear in the LES formalism. DNS provides fully resolved flow fields and flow statistics for a-priori subgrid scale analysis and a-posteriori LES validation.

Engineering and CFD

Principal Investigator: Peter Sanders , Institute of Theoretical Informatics, Karlsruhe Institute of Technology (Germany)

HPC Platform used: JUQUEEN of JSC

Local Project ID: hka17

Sorting is one of the most fundamental and widely used algorithms. It can be used to build index data structures, e.g., for full text search or for various applications in bioinformatics. Sorting can also rearrange data for further processing. In particular, it is a crucial tool for load balancing in advanced massively simulations. The wide variety of applications means that we need fast sorting algorithms for a wide spectrum of situations. Researchers have developed massively parallel robust sorting algorithms, apply new load balancing techniques, and systematically explore the design space of parallel sorting algorithms.

Engineering and CFD

Principal Investigator: Hening Bockhorn , Engler-Bunte-Institute/Combustion Technology, Karlruhe Institute of Technology (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: Cnoise

Direct numerical simulation (DNS) has been applied to study the noise emitted by combustion processes. A highly efficient numerical tool based on the public domain code OpenFOAM has first been developed for DNS of chemically reacting flows, including detailed calculations of transport fluxes and chemical reactions. It has then be used to simulate different turbulent flame configurations to gain an insight into the flame-turbulence interaction, which represents the main noise generation mechanisms. Based on the DNS results, simple correlation models have been developed to predict combustion noise by means of unsteady heat release due to turbulent combustion.

Engineering and CFD

Principal Investigator: Martin Oberlack , Technische Universität Darmstadt (Germany)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr92la

Channel flows are important references for studying turbulent phenomena in a simplified setting. The present project investigates Couette flow, i.e. channel flow driven by a moving wall. Although important to many practical applications, Couette flows have been studied considerably less than other canonical flows, for (a) the experimental setup is very complex, and (b) long and wide structures are present which are characteristic to Couette-type flows. This accounts for long and wide computational domains, which make direct numerical simulations of Couette flow expensive. Even by applying permeable boundary conditions, i.e. blowing from the lower and suction from the upper wall, the Couette-type structures could not be destroyed. Instead,…

Engineering and CFD

Principal Investigator: Lewin Stein , Institut für Strömungsmechanik und Technische Akustik, Technische Universität Berlin (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: AcouTurb

A cavity in a turbulent gas flow often leads to an interaction of vortex structures and acoustics. By exploiting this interaction, in some applications sound can be suppressed: silencers for jet engines or exhausts. In other cases, sound can be equally produced: squealing of open wheel-bays, sunroof and window buffeting, noise of pipeline intersection and tones of wind instruments. Typically, in expansive experimental runs, various configurations are tested in order to fulfill the design objectives of the respective application. Based on a 'Direct Numerical Simulation', the aim is to improve the understanding of the interactions between turbulence and acoustics of cavity resonators and to develop standalone sound prediction models, which…

Engineering and CFD

Principal Investigator: Thorsten Lutz , Institute of Aerodynamics and Gas Dynamics, University of Stuttgart (Germany)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr94va

Researchers of the Institute of Aerodynamics and Gas Dynamics (IAG) at the University of Stuttgart investigate the aerodynamic behaviour of modern wind turbines by means of CFD, using the finite volume code FLOWer. The main topics of interest are the effects on the turbine loads caused by turbulent inflow conditions and their control by active trailing edge flaps, and the analysis of the complex flow around the nacelle. Additional studies are currently conducted regarding the effects of aero-elasticity and impact of complex terrain.

Engineering and CFD

Principal Investigator: Christian Breitsamter , Chair of Aerodynamics and Fluid Mechanics, Technical University of Munich (Germany)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr86fi

The project focuses on the one hand on the improvement of flow physics knowledge related to flow separation at highly swept wing leading-edges resulting in large scale vortical structures. The evolution and development of such leading-edge vortices along with inherent instability mechanisms are still hard to be correctly predicted by numerical simulations. Special attention is needed on turbulence modelling and scale resolving techniques enabling also flow control methodologies for such types of flow. On the other hand, aerodynamic features of elasto-flexible lifting surfaces have been studied.

Engineering and CFD

Principal Investigator: Philipp Neumann , Scientific Computing Group, Universität Hamburg (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: GCS-mddc

The coalescence of nano-droplets is investigated using the highly optimized molecular dynamics software ls1 mardyn. Load balancing of the inhomogeneous vapor-liquid system is achieved through k-d trees, augmented by optimal communication patterns. Several solution strategies that are available to compute molecular trajectories on each process are considered, and the best strategy is automatically selected through an auto-tuning approach. Recent simulations that focused on large-scale homogeneous systems were able to leverage the performance of the entire Hazel Hen supercomputer, simulating for the first time more than twenty trillion molecules at a performance of up to 1.33 Petaflops.

Engineering and CFD

Principal Investigator: Manuel Keßler , Institut für Aerodynamik und Gasdynamik, Universität Stuttgart (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: HELISIM

Researchers of the Insitute of Aerdynamics and Gasdynamics at the University of Stuttgart leverage high-performance computing to analyse the behaviour of helicopters during various states of flight. Investigations range from deep analyses of fundamental aerodynamic phenomena like dynamic stall on the retreating blade to surveys over a broad spectrum of flight states over the full flight envelope of new configurations, to reduce flight mechanical risks. Recently, the group was able to simulate the first robust representation of the so-called tail-shake phenomenon—an interference between the aerodynamic wake of the rotor and upper fuselage and the tail boom with its elastic behaviour.

Engineering and CFD

Principal Investigator: Manuel Keßler, Institut für Aerodynamik und Gasdynamik , Universität Stuttgart

HPC Platform used: Hazel Hen of HLRS

Local Project ID: CARo

Using state-of-the-art simulation technology for highly resolved computational fluid dynamics (CFD) solutions, the helicopter and aeroacoustics group at the Institute of Aerodynamics and Gasdynamics at the University of Stuttgart has simulated the complex aerodynamics, aeromechanics, and aeroacoustics of rotorcraft for years. By advancing the established flow solver FLOWer, which now integrates higher order accuracy and systematic concentration of spatial resolution in targeted regions, the IAG-based group was able to obtain results for complete helicopters at certification-relevant flight states within the variance of individual flight tests for the aerodynamic noise.

Engineering and CFD

Principal Investigator: Dirk Pflüger , Institute for Parallel and Distributed Systems, University of Stuttgart (Germany)

HPC Platform used: Hazel Hen (HLRS)

Local Project ID: exaHD

The generation of clean, sustainable energy from plasma fusion reactors is currently limited by the presence of microinstabilities that arise during the fusion process, despite international efforts such as the ITER experiment, currently under construction in southern France. Numerical simulations are crucial to understand, predict, and control plasma turbulence with the help of large-scale computations. Due to the high dimensionality of the underlying equations, the fully resolved simulation of the numerical ITER is out of scope with classical discretization schemes, even for the next generation of exascale computers. With five research groups from mathematics, physics, and computer science, the SPPEXA project EXAHD has proposed to use a…

Engineering and CFD

Principal Investigator: Eckart Laurien , Institute of Nuclear Energy and Energy Systems (IKE), University of Stuttgart (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: DNSTHTS

In the quest for efficiency enhancement in energy conversion, supercritical carbon dioxide (sCO2) is an attractive alternative working fluid. However, the heat transfer to sCO2 is much different in the supercritical region than the subcritical region due to the strong variation of thermophysical properties which bring the effects of flow acceleration and buoyancy. The peculiarity in heat transfer and flow characteristics cannot be predicted accurately by using conventional correlations or Reynolds-Averaged Naiver-Stokes (RANS) simulations based on the turbulence models. Therefore, direct numerical simulation (DNS) is used in this ongoing project. In DNS, the Naiver-Stokes equations are numerically solved without any turbulence models. For…

Engineering and CFD

Principal Investigator: Sabine Roller , University of Siegen, Institute of Simulation Techniques and Scientific Computing (Germany)

HPC Platform used: SuperMUC (LRZ)

Local Project ID: pr84xu

This project was part of the ExaFSA project that investigates the possibility to exploit high-performance computing systems for integrated simulations of all parts contributing to noise generation in flows around obstacles. Such computations are challenging, as they involve the interaction of various physical effects on different scales. In this context, the compute time on SuperMUC granted for this project was used to particularly investigate the coupling of the flow within a large acoustic domain with individual discretization methods.

Engineering and CFD

Principal Investigator: Philipp Gerstner , Engineering Mathematics and Computing Lab (EMCL), Ruprecht-Karls-Universität Heidelberg (Germany)

HPC Platform used: JUQUEEN (JSC)

Local Project ID: hka14

The dynamic behaviour of fluid motion is driven by processes on a wide range of spatial and temporal scales. In a project run by Heidelberg University scientists, parts of model systems that describe fluid dynamics and temperature evolution were investigated. The models are formulated in terms of velocity, temperature, pressure, and density. The researchers employ a hierarchy of different physical models with an increasing degree of complexity. Additionally, uncertain input parameters are taken into account.

Engineering and CFD

Principal Investigator: Olga Shishkina , Max Planck Institute for Dynamics and Self-Organization, Göttingen (Germany)

HPC Platform used: SuperMUC (LRZ)

Local Project ID: pr94na

The characteristic patterns seen on the solar surface, on gas giants, in Earth's atmosphere and oceans, and many other geo- and astrophysical settings originate from turbulent convection dynamics flows driven by a density difference caused by, for instance, a temperature gradient. Convection in itself is inherently complex, but often it is the interaction with other forces, such as the Coriolis and Lorentz force due to rotation and magnetic fields, that determines the actual shape and behaviour of the flow structures. Understanding these convective patterns is often essentially tantamount to understanding the underlying physics at play. In this project, surveys through the huge parameter space are conducted, to not only categorise flow…

Engineering and CFD

Principal Investigator: Prof. Dr.- Ing. Oskar J. Haidn , TUM Department of Mechanical Engineering, Technical University of Munich (Germany)

HPC Platform used: SuperMUC (LRZ)

Local Project ID: pr83bi

Researchers at the Chair of Turbomachinery and Flight Propulsion (LTF) at the Technical University Munich numerically investigate flow and combustion in rocket engines using “green” propellants. The current focus involves researching methane/oxygen as a propellant combination, promising to be a good replacement for the commonly used hydrazine, offering good performance, storability, and handling qualities, while also being significantly less toxic. The goal of the project is an improved understanding of the relevant physical processes and a reliable prediction of thermal loads on the combustor.

Engineering and CFD

Principal Investigator: Jörg Schumacher , Technische Universität Ilmenau (Germany)

HPC Platform used: JUQUEEN (JSC)

Local Project ID: hil09

In many turbulent convection flows in nature and technology the thermal diffusivity is much higher than the kinematic viscosity which means that the Prandtl number is very low. Applications of this regime reach from deep solar convection, via convection in the liquid metal core of the Earth to liquid metal batteries for grid energy storage and nuclear engineering technology. Laboratory experiments in low-Prandtl-number convection for Pr < 0.1 have to be conducted in liquid metals which are inaccessible for laser imaging techniques and require analysis by ultrasound or X-rays. Direct numerical simulations of this regime of turbulent convection at high Rayleigh numbers are the only way to reveal the full three-dimensional structure of…

Engineering and CFD

Principal Investigator: Peter Gerlinger , Institut für Verbrennungstechnik der Luft- und Raumfahrt, Universität Stuttgart (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: SCRCOMB

At the Institute of Combustion Technology for Aerospace Engineering (IVLR) of the University of Stuttgart a team of scientists numerically investigates reacting flows at conditions typical for modern space transportation systems. The goal of the project is the better understanding of the ongoing processes in the combustion chambers and an improvement of the thermal load predictions. The research is integrated into the program "Technological Foundations for the Design of Thermally and Mechanically Highly Loaded Components of Future Space Transportation Systems" funded by the DFG.

Engineering and CFD

Principal Investigator: Wolfgang Schröder , Institute of Aerodynamics, RWTH Aachen University (Germany)

HPC Platform used: Hazel Hen (HLRS) and JUQUEEN (JSC)

Local Project ID: gcs_jean, chac30

A research group from the Institute of Aerodynamics (AIA) of the RWTH Aachen University utilized the computing power of Hazel Hen for large-scale simulations to analyze the intricate wake flow phenomena of space launchers. The objective of the project is the fundamental understanding of the origin of so called buffet loads acting on the nozzle which can lead to critical structural damage and to develop flow control devices to increase the efficiency and reliability of orbital transportation systems necessary for the steadily increasing demand for communication and navigation satellites.

Engineering and CFD

Principal Investigator: Aman G. Kidanemariam and Markus Uhlmann , Computational Fluid Dynamics group, Institute for Hydrodynamics, Karlsruhe Institute of Technology (KIT), Germany

HPC Platform used: SuperMUC (LRZ)

Local Project ID: pr84du

This project has investigated the problem of sediment transport and subaqueous pattern formation by means of high-fidelity direct numerical simulations which resolve all the relevant scales of the flow and the sediment bed. In order to realistically capture the phenomenon, sufficiently large computational domains with up to several billion grid nodes are adopted, while the sediment bed is represented by up to a million mobile spherical particles. The numerical method employed features an immersed boundary technique for the treatment of the moving fluid-solid interfaces and a soft-sphere model to realistically treat the inter-particle contacts. The study provides, first and foremost, a unique set of spatially and temporally resolved…

Engineering and CFD

Principal Investigator: 1) Markus Uhlmann, 2) Marco Mazzuoli , 1) Karlsruhe Institute of Technology/KIT (Germany), 2) University of Genoa (Italy)

HPC Platform used: SuperMUC (LRZ)

Local Project ID: pr87yo

Open channel flow can be considered as a convenient "laboratory" for investigating the physics of the flow in rivers. One open questions in this field is related to the influence of a rough boundary (i.e. the sediment bed) upon the hydraulic properties, which to date is still unsatisfactorily modelled by common engineering-type formulae. The present project aims to provide the basis for enhanced models by generating high-fidelity data of shallow flow over a bed roughened with spherical elements in the fully rough regime. In particular, the influence of the roughness Reynolds number and of the spatial roughness arrangement upon the turbulent channel flow structure is being studied.

Engineering and CFD

Principal Investigator: Torsten Auerswald and Jens Bange , Center for Applied Geoscience, University of Tübingen (Germany)

HPC Platform used: Hermit and Hornet of HLRS

Local Project ID: WAF

This project aims at the simulation of the influence of a turbulent atmospheric boundary layer flow on a wing. For this purpose the compressible flow solver DLR-TAU is used, which is developed by the German Aerospace Center (DLR). For initialising the simulation with a turbulent wind field a method to generate synthetic turbulence is used. This method uses statistics from measured time series from the atmospheric boundary layer to generate a threedimensional turbulent wind field which can be used as initial field in the flow simulations.

Engineering and CFD

Principal Investigator: Thorsten Lutz , Aircraft Aerodynamics Group, Institute of Aerodynamics and Gas Dynamics, University of Stuttgart (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: SCBOPT

In order to significantly reduce the drag and the environmental impact of future aircraft, considerable effort has to be undertaken in all fields of aircraft design. Besides reducing drag around the cruise condition of typical transport aircraft, it is also of great interest to expand the flight envelope in order to allow for a more flexible design. Understanding the behaviour of a commercial transport aircraft at the limits of its flight envelope, away from its design point, requires either expensive flight testing, tests in sophisticated wind tunnel facilities or advanced computational models. As flight tests are very expensive and take place in a late phase during the development of a new aircraft, when most of the design is already…

Engineering and CFD

Principal Investigator: Bernhard Weigand , Institute of Aerospace Thermodynamics, University of Stuttgart (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: FS3D

The subject of multiphase flows encompasses many processes in nature and a broad range of engineering applications such as weather forecasting, fuel injection, sprays, and the spreading of substances in agriculture. To investigate these processes the Institute of Aerospace Thermodynamics (ITLR) uses the direct numerical simulation (DNS) in-house code Free Surface 3D (FS3D). The code is continually optimized and expanded with new features and has been in use for more than 20 years. Investigations were performed, for instance, for phase transitions like freezing and evaporation, basic drop and bubble dynamics processes, droplet impacts on a thin film (“splashing”), and primary jet breakup as well as spray simulations, studies involving…

Engineering and CFD

Principal Investigator: Claus-Dieter Munz , Institute of Aerodynamics and Gas Dynamics, University of Stuttgart (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: HPCDG

The reduction of aeroacoustic noise emissions from technical systems like wind turbines or airplanes is a today’s key research goal. Understanding the intricate interactions between noise generation and flow field requires the full resolution of all flow features in time and space. Thus, very highly resolved unsteady simulations producing large amounts of data are required to get insight into local noise generation mechanisms and to investigate ideas for reduction. These mechanisms have been investigated by researchers at the University of Stuttgart through direct numerical simulation (DNS) of a generic airfoil configuration on Hazel Hen at HLRS. The results help to understand noise generation from turbulent flows and also serve as a…

Engineering and CFD

Principal Investigator: Dr.-Ing. Marcel Pfeiffer (IRS), Prof. Dr.-Ing. Stefanos Fasoulas, Prof. Dr. Claus-Dieter Munz (IAG) , University of Stuttgart, (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: IMPD

The Institute of Space Systems (IRS) and the Institute of Aerodynamics and Gas Dynamics (IAG) at the University of Stuttgart cooperatively develop the particle simulation tool "PICLas", a flexible simulation suite for the computation of three-dimensional plasma flows. The tool enables the physically-accurate numerical simulation of non-equilibrium plasma and gas flows. The applications range from the atmospheric entry of spacecraft to laser-plasma interaction in material sciences. The high-fidelity numerical approach allows detailed insights in the physical phenomena and is made feasible by high-performance computing.

Engineering and CFD

Principal Investigator: Qiaoyan Ye and Oliver Tiedje , Fraunhofer Institute for Manufacturing Engineering and Automation, Stuttgart, (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: droplMP

Researchers carry out numerical simulations of spray painting processes using a commercial high-speed rotary bell atomizer within the frame of an ongoing project “smart spray painting process”. Using a commercial CFD-code, detailed numerical studies deal with the film formation of the paint liquid on the bell cup, the primary liquid breakup near the bell edge, the paint droplet trajectories, as well as the droplet impact onto solid surface. Simulation results deliver important information for understanding and optimization of the complicated spray painting processes.

Engineering and CFD

Principal Investigator: P. Karthick Selvam , Institute of Nuclear Technology and Energy Systems (IKE), University of Stuttgart (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: LESHTCF

Understanding the nature of the turbulent flow mixing behavior in power plants which induce thermal fatigue cracking of components is still an unresolved challenge. Aside from measurements being performed at realistic power plant conditions (e.g. at 8 MPa pressure and temperature difference of 240°C between the mixing fluids) numerical calculations involving high-performance computing could throw more light into the complex fluid flow at any location of interest to investigators. Thus a combination of measurements coupled with numerical calculations could positively contribute towards realistic assessment of thermal fatigue damage induced in power plant components.

Engineering and CFD

Principal Investigator: Michael Gauding , Université de Rouen, Rouen (France)

HPC Platform used: JUQUEEN of JSC

Local Project ID: hfg00

Viscosity represents the most important property of turbulent flows, yet its impact of its variation on turbulence dynamics is not yet fully understood. This project addresses how the dissipation mechanism and self-similarity of turbulent flows are affected by fluctuations in viscosity—questions that can help lead to better turbulent mixing models, and, in turn, improved predictions of pollutants in combustion engines. Highly resolved direct numerical simulations of turbulent shear flows on JUQUEEN with up to 231 billion grid points were performed in pursuit of an answer to this question.

Engineering and CFD

Principal Investigator: Matthias Meinke , Chair of Fluid Mechanics and Institute of Aerodynamics (AIA), RWTH Aachen University, Aachen (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: NRoJ

Noise reduction is a key goal in European aircraft policy. One of the major noise sources at aircraft take-off is the engine jet noise. Recently, chevron nozzles were introduced which have drawn a lot of attention in research and the aircraft industry. Since the flow structures in the jet depend on the details of the nozzle exit geometry and have a large impact on the noise sources in the jet, scientists of the RWTH Aachen University extensively investigate chevron nozzles by running large-scale simulations based on a highly resolved mesh with up to 1 billion mesh cells.

Engineering and CFD

Principal Investigator: Harald Köstler , Friedrich-Alexander Universität Erlangen-Nürnberg (Germany)

HPC Platform used: JUQUEEN of JSC

Local Project ID: her18

With the rapidly changing massively parallel computer architectures arising in recent years, it became a huge challenge to make efficient use of contemporary supercomputers. Project ExaStencils addresses this problem by providing an easy-to-use, multi-layered domain-specific language to the application programmer such that problems can be formulated in an intuitive way fitting to different levels of abstraction. The necessary code transformations are performed by a special-purpose compiler framework that is able to produce scalable and efficient code that runs on large supercomputers like JUQUEEN of JSC.

Engineering and CFD

Principal Investigator: Malte Hoffmann, Claus-Dieter Munz , Institute of Aerodynamics and Gas Dynamics, University of Stuttgart (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: hpcHONK

Wind turbines are becoming increasingly efficient and quieter, while turbines operate reliably at high pressures and temperatures, and aircrafts use less fuel. These and other technical advances are made possible in great part because the occurring flow fields can be simulated with great accuracy on modern supercomputers. These machines use one hundred thousand processors and more to perform their calculations. The programs that are to run on such devices must be adapted to this high number of processors. An interdisciplinary team, which includes researchers of several institutes of the University of Stuttgart, has developed such a software package to enable two-phase flow simulations, where gaseous and liquid phases coexist. 

Engineering and CFD

Principal Investigator: Jörn Sesterhenn , CFD - Technische Universität Berlin (Germany)

HPC Platform used: Hermit/Hornet/Hazel Hen of HLRS

Local Project ID: ARSI

Supersonic impinging jets can be found in different technical applications of aerospace engineering. Depending on the flow conditions, loud tonal noise can be emitted. The so-called impinging tone is investigated by researchers of the chair of computational fluid dynamics at the Technical University of Berlin. Using direct numerical simulations (DNS) carried out on the Cray HPC systems Hermit, Hornet and Hazel Hen of the HLRS, the underlying sound source mechanisms could be identified for a typical configuration.

Engineering and CFD

Principal Investigator: Markus J. Kloker, Ulrich Rist , Institute for Aerodynamics and Gas Dynamics, University of Stuttgart (Germany)

HPC Platform used: Hornet/Hazel Hen of HLRS

Local Project ID: LAMTUR

The flow layer near the surface of a body - the boundary layer - can have a smooth, steady, low-momentum laminar state, but also an unsteady, turbulent, layer-stirring state with increased friction drag and wall heat flux. Wall heating is especially severe with supersonic hot gas flows like, e.g., in a rocket (Laval-) nozzle extension. To protect the walls from thermal failure a cooling gas is injected building a cooling film. Its persistence depends strongly on the layer state of the hot-gas flow, the type of cooling gas, and the form and strength of injection. Fundamental studies are performed using direct numerical simulations, providing also valuable benchmark data for less intricate computational-fluid-dynamics methods using turbulence…

Engineering and CFD

Principal Investigator: Jörn Sesterhenn , CFD - Technische Universität Berlin (Germany)

HPC Platform used: Hermit/Hornet/Hazel Hen of HLRS

Local Project ID: NOIJ

As part of the collaborative research centre CRC 1029, impingement cooling is studied at the chair of computational fluid dynamics at the Technical University of Berlin. The project aims at a more efficient cooling of turbine blades. This is necessary since future combustion concepts within gas turbines bring much higher thermal loads. Large scale direct numerical simulations (DNS) are carried out using the Cray supercomputers Hermit, Hornet and Hazel Hen of the HLRS.

Engineering and CFD

Principal Investigator: Tobias Loose , Ingenieurbüro Loose, Wössingen (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: HPC_welding

As an integral part of the PRACE SHAPE project HPC Welding, the parallel solvers of the Finite Element Analysis software LS-DYNA were used by Ingenieurbüro Tobias Loose to perform a welding analysis on HLRS HPC system Hazel Hen. A variety of test cases relevant for industrial applications had been set up with DynaWeld, a welding and heat treatment pre-processor for LS-DYNA, and were run on different numbers of compute cores to test its scaling capabilities.

Engineering and CFD

Principal Investigator: Apl.-Prof. Dr. P. Gerlinger , Institute of Combustion Technology, German Aerospace Center (DLR), Stuttgart (Germany)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr87zi

Researchers at the Institute of Combustion Technology at the German Aerospace Center (DLR) use petascale HPC system SuperMUC at LRZ in Munich for the simulation of soot evolution in lifted, turbulent, ethylene-air jet flames. The scope of their work is to develop and analyze simulation techniques for turbulent combustion with focus on soot predictions. The long-term objective is to develop validated high fidelity simulation techniques for soot predictions in turbulent combustion systems such as aeroengines.

Engineering and CFD

Principal Investigator: 1) Axel Klawonn, 2) Oliver Rheinbach , 1) Mathematical Institute of the University of Cologne (Germany), 2) Institute of Numerical Analysis and Optimization, Technische Universität Bergakademie Freiberg (Germany)

HPC Platform used: JUQUEEN of JSC

Local Project ID: hfg01

The project EXASTEEL is concerned with parallel implicit solvers for multiscale problems in structural mechanics discretized using finite elements. It is focussed on modern high strength steel materials. The higher strength and better ductility of these materials largely stems from the carefully engineered grain structure at the microscale. The computational simulations used therefore take into account the microstructure, but without resorting to a brute force discretization (which will be out of reach for the foreseeable future). The researchers' approach combines a computational multiscale approach well known in engineering (FE) with state-of-the-art parallel scalable iterative implicit solvers developed in mathematics. 

Engineering and CFD

Principal Investigator: Christian Hasse , Numerical Thermo-Fluid Dynamics, Technische Universität Bergakademie Freiberg (Germany)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr83xa

The direct numerical simulation performed in the course of this project – run on SuperMUC at LRZ – investigated a temporally evolving non-premixed syngas jet flame. Results of this simulation were used to validate a recently published set of extended model equations for the reaction zone dynamics in non-premixed combustion. Furthermore, the dataset was used to analyze the importance of curvature induced transport phenomena. Regions could be identified where curvature has a significant impact on the flame structure.

Engineering and CFD

Principal Investigator: Michael Breuer , Department of Fluid Mechanics, Helmut-Schmidt-University, Hamburg (Germany)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr84na

The interaction between a turbulent flow field and light-weight structural systems is the main topic of the present research project aiming at the development of advanced computational methodologies for this kind of multi-physics problem denoted fluid-structure interaction (FSI). This should allow to predict these complex coupled problems more reliably and to get closer to reality. An original computational methodology based on advanced techniques on the fluid and the structure side has been developed especially for thin flexible structures in turbulent flows.

Engineering and CFD

Principal Investigator: Dominique Thévenin , Lab. of Fluid Dynamics and Technical Flows, University of Magdeburg "Otto von Guericke", Magdeburg (Germany)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr84qo

Spray evaporation and burning in a turbulent environment is a configuration found in many practical applications, such as diesel engines, direct-injection gasoline engines, gas turbines, etc. Understanding the physical process involved in this combustion process will help improving the combustion efficiency of these devices and, therefore, reduce their emissions. Direct numerical simulation (DNS) is a very attractive tool to investigate in all details the underlying processes since it is able to capture and resolve all scales in the system. In this project, evaporation, ignition, and mixing are investigated in both temporally- and spatially-evolving jets, using DNS.

Engineering and CFD

Principal Investigator: Jörg Schumacher , Technische Universität Ilmenau (Germany)

HPC Platform used: JUQUEEN of JSC

Local Project ID: hil09

In many turbulent convection flows in nature and technology the thermal diffusivity is much higher than the kinematic viscosity which means that the Prandtl number is very low. Laboratory experiments in very low-Prandtl-number convection have to be conducted in liquid metals which are inaccessible for laser imaging techniques and require analysis by ultrasound or X-rays. Researchers of the TU Ilmenau and the Occidental College Los Angeles ran direct numerical simulations of this regime of turbulent convection at high Rayleigh numbers to reveal the full 3D structure of temperature and velocity fields.

Engineering and CFD

Principal Investigator: Sabine Roller , University of Siegen, Institute of Simulation Techniques and Scientific Computing (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: PP14112730

The electro-dialysis process is an efficient desalination technique that uses ion exchange membranes to produce clean water from seawater. This process involves different physical phenomena like fluid dynamics, electrodynamics and diffusive mass-transport along with their interactions. Rigorous assessment of those interactions, especially those near the membranes, are only possible through large-scale coupled simulations. The aim of the APAM compute time project is the detailed flow simulation in this application to understand the effect of different spacer structures between the membranes in this process.

Engineering and CFD

Principal Investigator: Christian Hasse , Numerical Thermo-Fluid Dynamics, Technische Universität Bergakademie Freiberg (Germany)

HPC Platform used: Hornet of HLRS

Local Project ID: ICECCV

A numerical research project, run on Hornet of HLRS, focused on the grid of internal combustion (IC) engines in the vicinity of the intake valve and its effect on the simulation results. The overall goal was to develop a methodology for a quantitative comparison of different results in terms of the intake jet as well as the identification of crucial mesh regions.

Engineering and CFD

Principal Investigator: Jonas Wack , Institute of Fluid Mechanics and Hydraulic Machinery, University of Stuttgart (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: hyperbol

In the last decades, hydraulic machines have experienced a continual extension of the operating range in order to integrate other renewable energy sources into the electrical grid. When operated at off-design conditions, the turbine experiences cavitation which may reduce the power output and can cause severe damage in the machine. Cavitation simulations are suitable to give a better understanding of the physical processes acting at off-design conditions. The goal of this project is to give an insight in the capabilities of two-phase simulations for hydraulic machines and determine the range for safe operation.

Engineering and CFD

Principal Investigator: Bernd Junginger , Institute of Fluid Mechanics and Hydraulic Machinery, University of Stuttgart (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: axialgap

The operation range of hydraulic turbines is increasing more and more to guarantee the power system stability of the electric grid due to the increased amount of electric power generated by unregulated renewable energy like wind and photovoltaic. Therefore, hydraulic turbines are operated in off-design conditions where highly transient phenomena can occur. Standard approaches which are used for the design process of hydraulic machines are no longer suitable to predict the correct flow field in these operating points. Advanced turbulence models and high mesh resolutions are applied to increase the accuracy of the simulations.

Engineering and CFD

Principal Investigator: Bernd Budich , Technische Universität München (Germany)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr85ki

A project carried out by a team of scientists from the Institute of Aerodynamics and Fluid Mechanics at the Technische Universität München focused on the numerical investigation of cavitating flow in the context of ship propellers. A key aspect of this project was to develop the ability to assess local flow aggressiveness and to quantify the potential of material erosion.

Engineering and CFD

Principal Investigator: Detlef Lohse , University of Twente (The Netherlands)

HPC Platform used: Hermit of HLRS

Local Project ID: PP12061135

Rayleigh-Benard flow (the flow in a box heated from below and cooled from above) and Taylor-Couette flow (the flow between two counter-rotating cylinders) are the two paradigmatic systems in the physics of fluids, and many new concepts have been tested with them. Researchers from the Physics of Fluids group at the University of Twente have been carrying out simulations of these systems on HLRS supercomputers to try and improve our understanding of turbulence.

Engineering and CFD

Principal Investigator: Walter Boscheri , Department of Civil, Environmental and Mechanical Engineering, University of Trento (Italy)

HPC Platform used: SuperMUC of LRZ

Local Project ID: stimulus

Researchers leveraged the computing power of SuperMUC for the development of finite volume Lagrangian numerical schemes on multidimensional unstructured meshes for fluid dynamic problems. The numerical algorithms developed in project STiMulUs are designed to be high order accurate in space as well as in time, requiring even more information to be updated and recomputed continuously as the simulation goes on.

Engineering and CFD

Principal Investigator: Manuel Keßler , Institut für Aerodynamik und Gasdynamik, Universität Stuttgart (Germany)

HPC Platform used: Hornet and Hazel Hen of HLRS

Local Project ID: DGDES

Despite the great success of current state-of-the-art fluid flow solvers, the continuing development of computing hardware necessitates new numerical methods for flow simulations. High order methods on unstructured grids like Discontinuous Galerkin discretisations deliver highly accurate results and allow for unprecedented parallelisation efficiency at huge numbers of cores. The project aims to transfer the infrastructure technology (overlapping Chimera grids, mesh movement and deformation, convergence acceleration) from conventional to such advanced solvers to allow application to relevant engineering problems like helicopter simulations in the mid-term future.

Engineering and CFD

Principal Investigator: Manuel Keßler , Institut für Aerodynamik und Gasdynamik (IAG), Universität Stuttgart (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: HELISIM

The helicopter and aeroacoustics group of IAG runs extensive aerodynamics and aeromechanics simulations of rotorcraft in order to understand not only basic parameters as power requirements or loads on the rotor blades but also to predict acoustic footprints and gain a deeper insight into the interactions between different helicopter components. For this purpose, the group runs simulation setups on HLRS supercomputer Hazel Hen of a magnitude beyond 200 million cells with fifth order accuracy and even up to half a billion cells for selected cases, delivering results directly comparable to real flight test data at unparalleled accuracy.

Engineering and CFD

Principal Investigator: Erol Oezger , Technische Hochschule Ingolstadt (Germany)

HPC Platform used: Hermit and Hornet of HLRS

Local Project ID: DWLBM

The project Investigation of Delta Wing Time Dependent Flow Characteristics with Lattice-Boltzmann Method is carried out by the Technische Hochschule Ingolstadt, Faculty of Mechanical Engineering, at the High Performance Computing Center Stuttgart. It focuses on the numerical investigation of the delta wing flow under various aspects such as sweep angle variation, sharp or round leading edges, as well as high and lower Reynolds numbers with a Lattice-Boltzmann PowerFLOW solver provided by Exa.

Engineering and CFD

Principal Investigator: Javier Jiménez , Universidad Politécnica de Madrid (Spain)

HPC Platform used: SuperMUC of LRZ

Local Project ID: PR_2016_01

An international research project aimed at investigating the structure and dynamics of wall-bounded turbulence in adverse pressure gradient environments has resulted in the first Direct Numerical Simulation (DNS) of a self-similar turbulent boundary layers (TBL) in a strong adverse pressure gradient (APG) environment at the verge of separation up to a Reynolds number based on the momentum thickness of 104.

Engineering and CFD

Principal Investigator: Markus Uhlmann , Karlsruhe Institute of Technology (Germany)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr83la

Turbulent flow seeded with solid particles is encountered in a number of natural and man-made systems. Many physical effects occurring when the fluid and the solid phase interact strongly so far have obstinately resisted analytical and experimental approaches – sometimes with far reaching consequences in various practical applications. Using SuperMUC, researchers simulated with unprecedented detail the turbulent flow in an unbounded domain in the presence of suspended, heavy, solid particles in order to understand and describe the dynamics of such particulate flow systems with sufficient accuracy.

Engineering and CFD

Principal Investigator: Markus Uhlmann , Karlsruhe Institute of Technology (Germany)

HPC Platform used: Hornet of HLRS

Local Project ID: DNSDUCT

Researchers investigated the mechanism of secondary flow formation in open duct flow where rigid/rigid and mixed (rigid/free-surface) corners exist. Employing direct numerical simulations (DNS) on HLRS high performance computing system Hornet, the scientists aimed at generating high-fidelity data in closed and open duct flows by means of pseudo-spectral DNS and at analysing the flow fields with particular emphasis on the dynamics of coherent structures.

Engineering and CFD

Principal Investigator: Petros Koumoutsakos , Computational Science & Engineering Laboratory, ETH Zurich (Switzerland)

HPC Platform used: JUQUEEN of JSC

Local Project ID: PRACE091

Leveraging the petascale computing power of HPC system JUQUEEN of the Jülich Supercomputing Centre, researchers at the Chair of Computational Science at ETH Zurich performed unprecedented large-scale simulations of cloud cavitation collapse with up to 75’000 vapor cavities on resolutions of up to 0.5 trillion mesh cells and 25’000 time steps.

Engineering and CFD

Principal Investigator: Christoph Scheit , Lehrstuhl für Prozessmaschinen und Anlagentechnik, Friedrich-Alexander Universität Erlangen-Nürnberg (Germany)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr86xe

In order to gain a deeper understanding of the aerodynamic noise generation mechanisms and transmission for automotive applications, researchers from the Universität Erlangen leveraged HPC system SuperMUC of LRZ to develop a hybrid aeroacoustic method. The turbulent flow over a forward-facing step served as a test case for the final validation of a hybrid scheme for the computation of broadband noise, as caused typically by turbulent flows.

Engineering and CFD

Principal Investigator: Stefan Hickel , Technische Universität München (Germany)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr45tu

Researchers of the Technische Universität München conducted large-eddy simulations (LES) on HPC system SuperMUC of LRZ for numerical investigations of a pseudo-shock system. These pseudo-shock systems influence the reliability and performance of a wide range of flow devices, such as ducts and pipelines in the field of process engineering and supersonic aircraft inlets. Thus, the optimization of pseudo-shock systems is of great academic and commercial interest.

Engineering and CFD

Principal Investigator: Jörn Sesterhenn , CFD - Technische Universität Berlin (Germany)

HPC Platform used: Hermit of HLRS

Local Project ID: SBLI-SS

Shock-wave/boundary-layer interactions (SBLIs) play an important part in many engineering applications. They are common in internal and external aerodynamic flows. However, numerical treatment of such SBLIs is difficult as the important flow features place competing demands on the applied numerical algorithms. Using the HPC infrastructure provided by the HLRS, scientists of the Technische Universität Berlin performed a detailed direct numerical simulation of a transonic SBLI creating a detailed numerical database this way which is now available for further detailed studies.

Engineering and CFD

Principal Investigator: Wolfgang Schröder , Institute of Aerodynamics, RWTH Aachen University (Germany)

HPC Platform used: Hazel Hen of HLRS

Local Project ID: gcs-jean

Within the framework of a research project which aims at reducing the emission of CO2 by conventional coal-fired power plants through oxy-fuel combustion, scientists of the RWTH Aachen University simulated the heating processes of coal dust in order to gain a better understanding of the conditions causing carbon dust to ignite in an oxygen-carbon dioxide atmosphere. Since carbon particles are of irregular, non-spherical shape their motion is difficult to predict, thus simulations of large quantities of fully dissolved carbon particles moving freely in a turbulent flow require the availability of petascale HPC systems like Hazel Hen.

Engineering and CFD

Principal Investigator: Michael Breuer , Department of Fluid Mechanics, Helmut-Schmidt-University, Hamburg (Germany)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr47me

Fluid-Structure Interaction is a topic of major interest in many engineering fields. The significant growth of the computational capabilities allows solving more complex coupled problems, whereby the physical models get closer to reality. In order to simulate practically relevant light-weight structural systems in turbulent flows, scientists of the Helmut-Schmidt-University in Hamburg developed and implemented an original computational methodology especially for thin flexible structures in turbulent flows.

Engineering and CFD

Principal Investigator: Dr. Sylvain Reboux , ASCOMP AG, Zurich/Switzerland

HPC Platform used: Hermit of HLRS

Local Project ID: PP13081602

This project, for which HPC system Hermit of the High Performance Computing Center Stuttgart served as computing platform, is part of the NURESAFE initiative for nuclear safety. The objective was to develop a global modelling framework for multi-scale core thermal-hydraulics in Pressurized Water Reactors (PWR) as understanding heat transfer phenomena in turbulent bubbly flows is of great interest for the scientist community and for the industry.

Engineering and CFD

Principal Investigator: Claus-Dieter Munz , Institut für Aerodynamik und Gasdynamik, Universität Stuttgart (Germany)

HPC Platform used: Hornet of HLRS

Local Project ID: HPCDG

In order to analyse aeroacoustic noise generation processes, researchers from the Institute for Aerodynamics and Gas Dynamics performed high fidelity, large-scale flow and acoustic computations using the discontinuous Galerkin spectral element method on the HPC system Hornet at the High Performance Computing Center Stuttgart (HLRS). The aim of this investigation is to gain insight into the tonal noise generation process of a side-view mirror.

Engineering and CFD

Principal Investigator: Stefan Hickel , Technische Universität München (Germany)

HPC Platform used: Hermit of HLRS

Local Project ID: CMHF

A scramjet is an air breathing jet engine for hypersonic flight velocities of about ten to twenty times the speed of sound. Combustion, too, takes place at supersonic flow velocity, which requires a fast mixing of fuel and compressed airflow to enable combustion during the very short residence time of the reactants in the combustion chamber. To analyze the flame stabilization in the combustion chamber through a pilot injection of hydrogen and air at the base of the strut injector, researchers from the Technische Universität München (TUM) performed large-eddy simulations for a generic strut-injector geometry based on an experimental setup at the TUM.

Engineering and CFD

Principal Investigator: Harald Köstler , Lehrstuhl Informatik 10 (Systemsimulation), Universität Erlangen-Nürnberg (Germany)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr86ma

Researchers of the University of Erlangen applied the waLBerla Framework, a widely applicable lattice Boltzmann simulation code, on HPC system SuperMUC of LRZ to test the suitability of the software framework for different Computational Fluid Dynamics applications: One project focused on investigating collective swarming behavior of numerous self-propelled microorganisms at low Reynolds numbers, a second project implemented within waLBerla was the simulation of electron beam melting, while a third simulated the separation of charged macromolecules in electrolyte solutions inside channels of dimensions relevant for lab-on-a-chip (LoC) systems.

Engineering and CFD

Principal Investigator: Francesco Grasso , Institut Aérotechnique, Conservatoire National des Arts et Métiers, Saint-Cyr-l'Ecole (France)

HPC Platform used: JUQUEEN of JSC

Local Project ID: PRA084

Direct numerical simulation (DNS) of turbulent mixing layers has been possible only in relatively recent times. In an ambitious project using HPC system JUQUEEN of JSC, scientists analysed the process of mixing layer formation in a flow configuration with sizeable compressibility effects by numerically reproducing the flow conditions of a well documented flow case with two turbulent streams. Large-scale direct numerical simulation were performed in a wide computational domain which included the two upstream turbulent boundary layers developing on the two sides of a zero-thickness splitter plate and their early merging region. The complexity of the flow, the extent of the computational box and the mesh size made the study extremely…

Engineering and CFD

Principal Investigator: Claus-Dieter Munz , Institute of Aerodynamics and Gas Dynamics, University of Stuttgart

HPC Platform used: Hornet of HLRS

Local Project ID: XXL_lamtur

Scientists of the Institute of Aerodynamics and Gas Dynamics of the University of Stuttgart conducted a Direct Numerical Simulation of a spatially-developing supersonic turbulent boundary layer up to ReΘ=3878. For this purpose, they used the discontinuous Galerkin spectral element method (DGSEM), a very efficient DG formulation that is specifically tailored to HPC applications. It allowed the researchers to efficiently exploit the entire computational power available on the HLRS Cray XC40 supercomputer Hornet and to run the simulation with 93,840 processors without any performance losses. 

Engineering and CFD

Principal Investigator: Wolfgang Schröder , Institute of Aerodynamics, RWTH Aachen University (Germany)

HPC Platform used: Hornet of HLRS

Local Project ID: XXL_Jean

A research team of the Institute of Aerodynamics (AIA) of the RWTH Aachen University leveraged the petascale computing power of the HPC system Hornet for large-scale simulation runs which used the entirety of the system’s available 94,646 compute cores. The project “Large-Eddy Simulation of a Helicopter Engine Jet” aimed at analysing the impact of internal perturbations due to geometric variations on the flow field and the acoustic field of a helicopter engine jet. For this purpose, the researchers conducted highly resolved large-eddy simulations based on hierarchically refined Cartesian meshes up to 1 billion cells over a time span of 300 hours.

Engineering and CFD

Principal Investigator: Wolfgang Schröder , Institute of Aerodynamics, RWTH Aachen University (Germany)

HPC Platform used: Hornet of HLRS

Local Project ID: XXL_jean

Exploiting the available computing capacities of supercomputer Hornet of the High Performance Computing Center Stuttgart, researchers from the Institute of Aerodynamics (AIA) of the RWTH Aachen University conducted a large-scale simulation run in their efforts to tackle the prediction of the acoustic field of a low pressure axial fan using computational aeroacoustics (CAA) methods. Goal of this project, which scaled to 92,000 compute cores of the HPC system Hornet, was to achieve a better understanding of the development of vortical flow structures and the turbulence intensity in the tip-gap of a ducted axial fan.

Engineering and CFD

Principal Investigator: Sabine Roller , University of Siegen, Institute of Simulation Techniques and Scientific Computing

HPC Platform used: Hornet of HLRS

Local Project ID: XXL_ITCD

A research team of the Institute of Simulation Techniques and Scientific Computing of the University of Siegen leveraged the petascale computing power of HPC system Hornet for their research project Ion Transport by Convection and Diffusion. This large-scale simulation project stressed the available capacities of the HLRS supercomputer to its full extent as the simulation involved the simultaneous consideration of multiple effects like flow through a complex geometry, mass transport due to diffusion and electrodynamic forces. Goal of this project was to achieve a better understanding of the electrodialysis desalination process in order to identify methods and possibilities of how to optimize it.

Engineering and CFD

Principal Investigator: Markus Uhlmann , Institute for Hydromechanics, Karlsruhe Institute of Technology/KIT (Germany)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr58cu

A research project addressed the fundamental mechanisms and processes involved in the dynamics of a large number of rigid particles settling under the influence of gravity in an initially quiescent fluid, as well the characteristics of the particle-induced flow field.

Engineering and CFD

Principal Investigator: Daniela Gisele François , Institut für Strömungsmechanik, TU Braunschweig (Germany)

HPC Platform used: Hermit of HLRS

Local Project ID: NSESRSM

One of the major limiting factors of the flight operational range of transport aircraft is the inlet separation of engine. The overall aim of this project is to provide an efficient numerical method able to compute the large range of spectral scales present in flows during the separation process.

Engineering and CFD

Principal Investigator: Christian Breitsamter , AER/TU München (Germany)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr86fi

For delta and diamond wing configurations, the flow field is typically dominated by large scale vortex structures, which originate from the wing leading-edges. With increasing angle of attack, the flow structures grow in size and become more and more unsteady. By use of active and passive flow control mechanisms, the vortex characteristics can be manipulated and controlled in some extent.

Engineering and CFD

Principal Investigator: Mauro Sbragaglia , University of Roma (Italy)

HPC Platform used: Hermit of HLRS

Local Project ID: PP13081531

Scientists of the University of Rome (“Tor Vergata”) and the University of Eindhoven aimed to perform a systematic investigation of multi-component and/or multi-phase flow dynamics in porous matrices adopting a bottom-up, multi-scale approach based on a Lattice Boltzmann Method (LBM).

Engineering and CFD

Principal Investigator: Manfred Krafczyk , IRMB/TU Braunschweig (Germany)

HPC Platform used: Hermit of HLRS

Local Project ID: PS-LBM

Scientists of the Technische Universität Braunschweig conduct Direct Navier-Stokes (DNS) and Large Eddy Simulation (LES) computations of turbulent flows which explicitly take into account specific pore scale geometries obtained from computer tomography imaging and do not use any explicit turbulence modeling.

Engineering and CFD

Principal Investigator: Richard Jefferson-Loveday , The University of Nottingham (U.K.)

HPC Platform used: Hermit of HLRS

Local Project ID: PP13081626

With the projected demand for air transport set to double the world aircraft fleet by 2020 it is becoming urgent to take steps to reduce the environmental impact of take-off noise from aircraft. Scientists from the UK performed highly intensive Large Eddy Simulations (LES) of complex geometry jets with the major emphasis to use the LES CFD approach (Computational Fluid Dynamics) to enable improved prediction and to generate the necessary complex unsteady flow fields needed for acoustic modelling.

Engineering and CFD

Principal Investigator: Christian Egerer , AER/TU München (Germany)

HPC Platform used: SuperMUC (LRZ) / Hornet/Hermit (HLRS)

Local Project ID: LRZ Project ID: pr86ta / HLRS Project ID: LESCAV

Modern Diesel injection systems exceed injection pressures of 2000 bar in order to meet current and future emission regulations. By accelerating the flow through an injection nozzle or throttle valve pressure in the liquid can drop below vapor pressure, initiating local evaporation (hydrodynamic cavitation). The advection of vapor cavities into regions where the static pressure of the surrounding liquid exceeds vapor pressure leads to a sudden re-condensation or collapse of vapor cavities. The surrounding liquid is accelerated towards the center of the cavities and strong shock waves are emitted. The resulting pressure loads can lead to material erosion. For optimization of future fuel injectors the ability to predict cavitation and…

Engineering and CFD

Principal Investigator: Jörg Schumacher , TU Ilmenau (Germany)

HPC Platform used: JUQUEEN of JSC

Local Project ID: hil07

An international team of scientists conducted high-precision spectral element simulations which resolved the fine-scale structure of turbulent Rayleigh-Bénard convection, in particular the statistical fluctuations of the temperature and velocity gradients.

Engineering and CFD

Principal Investigator: Marc Ellero , Technische Universität München (Germany)

HPC Platform used: SuperMUC of LRZ

Local Project ID: MMPS

A team of scientists from Germany, UK, US and Spain have developed a multiscale particle methods framework based on Smoothed Particle Hydrodynamics (SPH) and the stochastic Smoothed Dissipative Particle Dynamics (SDPD) to simulate the complex dynamics of submicron-sized colloidal and large non-colloidal particles suspended in Newtonian and non-Newtonian fluids.

Engineering and CFD

Principal Investigator: Ulrich Tallarek , Philipps Universität Marburg

HPC Platform used: JUQUEEN of JSC

Local Project ID: hmr10

Liquid chromatography is an industrially relevant application of mass transport through a porous medium, where a fluid mix of chemical substances is separated into its components by passing through a cylindrical tube densely packed with solid, spherical adsorbent particles (the column). The number of chemical substances that can be separated by a column (its separation efficiency) is determined by how the packing particles are distributed over the column volume. 

Engineering and CFD

Principal Investigator: Nikolaus A. Adams , TU München

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr32ma

A team of scientists of the Institute of Aerodynamics and Fluid Mechanics of the Technische Universität München have developed a smoothed particle hydrodynamics (SPH) method to simulate complex multiphase flows with arbitrary interfaces and included a model for surface active agents (surfactants) [1]. In SPH the computational domain is discretized with particles that are moving in time.

Engineering and CFD

Principal Investigator: Benjamin Sauer , TU Darmstadt

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr47ve

Aircraft engines are equipped with airblast atomizers to assure the liquid fuel injection. During airblast atomization a thin liquid film is passed by coflowing air streams, leading to the disintegration of the liquid sheet. The breakup process is still not well understood, especially a detailed insight into the phenomena of primary breakup is a major limitation in understanding these flow systems. In this project the primary breakup of airblasted liquid sheets is investigated numerically. Highly resolved Direct Numerical Simulations (DNS) of this two-phase flows are performed on the GCS Supercomputer SuperMUC at Leibniz Supercomputing Centre.

Engineering and CFD

Principal Investigator: Rainer Grauer , Ruhr-Universität Bochum

HPC Platform used: JUQUEEN of JSC

Local Project ID: hbo40

The process in which a magnetic field is amplified by the flow of an electrically conducting fluid such as liquid metal or plasma, known as dynamo action, is believed to be the origin of magnetic fields in the universe including the magnetic field of the earth. Laboratory experiments using liquid sodium try to investigate the underlying mechanisms. Especially one setup has been successful in producing a dynamo with a free turbulent flow, the Von Karman Sodium experiment in Cadarache, consisting of a cylindrical vessel filled with liquid sodium, stirred by two counter-rotating soft-iron impellers.

Engineering and CFD

Principal Investigator: Feichi Zhang , Karlsruhe Institute of Technology

HPC Platform used: Hermit of HLRS

Local Project ID: Cnoise

The noise emitted from turbulent combustion belongs, similarly to the pollutant emissions, to the negative effects of combustion processes, i.e. noise pollution. The project’s main objective is to analyse in-depth the formation mechanism of noise generated from turbulent flames and to predict such noise radiations already during the development phase. 

Engineering and CFD

Principal Investigator: Franco Magagnato , Karlsruhe Institute of Technology

HPC Platform used: Hermit of HLRS

Local Project ID: fsm606_2

It is well known that in order to fulfil the stringent demands for low emissions of NOx, the lean premixed combustion concept is commonly used. However, lean premixed combustors are susceptible to thermo acoustic instabilities driven by the combustion process and possibly sustained by a resonant feedback mechanism coupling pressure and heat release. This resonant feed back mechanism creates pulsations typically in the frequency range of several hundred Hz and which reach high amplitudes so that the system has to be shut down or is even damaged. Although the research activities of the recent years have contributed to a better understanding of this phenomenon the underlying mechanisms are still not well enough understood.

Engineering and CFD

Principal Investigator: Gregor Gassner , Universität zu Köln

HPC Platform used: JUQUEEN of JSC

Local Project ID: hss14

The accurate simulation and modeling of turbulent fluid motion is a very important research subject in natural and engineering sciences. Ranging from the application in aircraft design, the aeroacoustic optimization of an automobile and the cooling of modern microprocessor devises, the efficient simulation of turbulence is a key technology in modern engineering and design of technical products and devices.

Engineering and CFD

Principal Investigator: Koen Hillewaert , Cenaero (Belgium)

HPC Platform used: JUQUEEN of JSC

Local Project ID: PRA072

Turbulence is pervasive in turbomachinery, and predicting its effect on the flow and performance is a major challenge for CFD (Computational Fluid Dynamics) tools. RANS (Reynolds-averaged Navier–Stokes) methods, modelling the averaged impact of turbulence, are currently the industrial standard. Scale-resolving approaches such as DNS (Direct Numerical Simulation) and LES (Large Eddy Simulation) compute either all turbulent structures directly, or only represent the larger, and model the impact of the smallest structures. 

Engineering and CFD

Principal Investigator: Olga Shishkina , German Aerospace Center (DLR)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr63ro

Turbulent thermal convection is of fundamental interest in many fields of physics and engineering. Examples to mention here are the convective flows in the Earth’s atmosphere and oceans, in its core and mantle, but also in the outer layer of stars, in chemical engineering or in aircraft cabins. Frequently, these systems are also strongly influenced by rotation.

Engineering and CFD

Principal Investigator: Bendiks Jan Boersma , Delft University of Technology (Netherlands)

HPC Platform used: Hermit of HLRS

Local Project ID: PP12061025

Turbulence is a flow regimen which is dominated by a wide range of length and time scales. The largest scale of motion depends on the geometry of the problem and the smallest scale of motion on the material properties of the liquid. In the atmosphere the largest scales of motion can be a few hundred kilometers big while the smallest scale of motion are a few millimeters. In an engineering application the largest scales of motion are much smaller than in the atmosphere but still there is a very big difference between the smallest and largest scale of motion. 

Engineering and CFD

Principal Investigator: Marc Buffat , Université Claude Bernard Lyon 1 (France)

HPC Platform used: JUQUEEN of JSC and SuperMUC of LRZ

Local Project ID: PRA058

Understanding the mechanisms involved in the turbulent transition in boundary layers is crucial for many engineering domains. The instabilities that develop in to those flows are highly non-linear and unsteady. They are mainly studied by analytical theories supplemented by direct numerical simulations (DNS) of the entire flow dynamics which must be sufficiently accurate to properly take into account all spatial and temporal characteristic scales and their non-linear interactions.

Engineering and CFD

Principal Investigator: Jörn Sesterhenn , Technische Universität Berlin

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr86po

Noise prediction is one of the most discussed topics for Computational Fluid Dynamics today due to the fact that noise optimization, energy saving and pollutant emission minimization complement each other. In a GCS Large Scale project headed by Professor Jörn Sesterhenn of the Technische Universität Berlin, numerical simulations of a supersonic jet were performed on HPC system SuperMUC of LRZ, focusing on the research of the acoustic field.

Engineering and CFD

Principal Investigator: Christian Engfer , DSI/IAG Universität Stuttgart

HPC Platform used: SuperMUC of LRZ

Local Project ID: h1142

The operation of the flying observatory SOFIA (Stratospheric Observatory For Infrared Astronomy), which was designed to look at celestial bodies in the infrared range of the electromagnetic spectrum from the lower stratosphere above the obscuring water vapor, presents some challenging aerodynamic and aero-acoustic problems.

Engineering and CFD

Principal Investigator: Peter Gerlinger , Universität Stuttgart

HPC Platform used: Hermit of HLRS

Local Project ID: SCRCOMB

At the Institute of Combustion Technology for Aerospace Engineering (IVLR) at the University of Stuttgart a team of scientists numerically investigates reacting flows at conditions typical for modern space transportation systems. The research is integrated into the programs SFB/TRR-40 (Technological Foundations for the Design of Thermally and Mechanically Highly Loaded Components of Future Space Transportation Systems) and GRK 1095/2 (Aero-Thermodynamic Design of a Scramjet Propulsion System) that are funded by the DFG (Deutsche Forschungsgemeinschaft).

Engineering and CFD

Principal Investigator: Frank Holzäpfel , German Aerospace Center (DLR)

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr63zi

As an unavoidable consequence of lift, aircraft generate a pair of counter-rotating and persistent wake vortices that may pose a potential risk to following aircraft. The highest risk to encounter wake vortices prevails in ground proximity, where the vortices cannot descend below the glide path but tend to rebound due to the interaction with the ground surface. 

Engineering and CFD

Principal Investigator: Claudia Günther , Institute of Aerodynamics, RWTH Aachen University (Germany)

HPC Platform used: Hermit of HLRS

Local Project ID: CombEng

To increase the efficiency and reduce the pollutant emissions of combustion engines, researchers simulate the complex flow field in internal combustion engines which has significant influence on the formation of the fuel-air-mixture in the combustion chamber and on the combustion process itself.

Engineering and CFD

Principal Investigator: Albert Ruprecht , Institute of Fluid Mechanics and Hydraulic Machinery, University of Stuttgart

HPC Platform used: Hermit of HLRS

Local Project ID: FENFLOSS

Today, hydropower is the most important and widely used renewable energy source. Due to the strong increase of fluctuating renewable energies, a great amount of regulating power is necessary in the net, which is mainly available from hydropower. As a consequence, the hydraulic turbines are very often operated in extreme off-design conditions.

Engineering and CFD

Principal Investigator: Markus J. Kloker , Institute of Aerodynamics and Gas Dynamics, University of Stuttgart (Germany)

HPC Platform used: Hermit of HLRS

Local Project ID: HBLT

A team of scientists from the Institute of Aerodynamics and Gas Dynamics of University of Stuttgart are performing direct numerical simulations and sophisticated stability analyses with regard to the so-called hypersonic flight, i.e.with the goal to be able to accelerate an aircraft to at least about five times the speed of sound.

Engineering and CFD

Principal Investigator: Ewald Krämer , Institute of Aerodynamics and Gas Dynamics, University of Stuttgart

HPC Platform used: Hermit of HLRS

Local Project ID: LAMTUR

Laminar Turbulent Transition in Aerodynamics Boundary Layers: Scientists from the Institute of Aerodynamics and Gas Dynamics of University Stuttgart are doing simulations on GCS supercomputers to achieve a comprehensive understanding of three-dimensional dynamic instability processes, which is a pre-requisite for successful Laminar Flow Control (LFC).

Engineering and CFD

Principal Investigator: Dr. Jenny Kremser , Automotive Simulation Center Stuttgart e.V. (ASC-S)

HPC Platform used: Hermit of HLRS

Local Project ID: e-gen

Project ‘Development and Validation of Thermal Simulation Models for Li-Ion Batteries in Hybrid and Pure Electric Vehicles’ (asc(s, Battery Design, CD-adapco, Daimler AG, Opel AG and Porsche AG) concentrates on the development of a simulation environment for the electro-thermal layout of a lithium ion battery module in a vehicle. The project team pursues the development of optimized design concepts for electrified vehicles to fulfill increasing demands on energy consumption, driving range, and durability.

Engineering and CFD

Principal Investigator: Stefan Hickel , Institute of Aerodynamics and Fluid Mechanics, Technische Universität München

HPC Platform used: SuperMUC of LRZ

Local Project ID: pr47bu

Delta wings, or wings with a triangular planform, are an important reference configuration for applied high-performance aerodynamics as well as for basic fluid mechanics studies.

Engineering and CFD

Principal Investigator: Johannes Roth , Institute for Theoretical and Applied Physics, University of Stuttgart

HPC Platform used: Hermit of HLRS

Local Project ID: LASMD

Laser ablation is a technology which gains increasingly more importance for drilling, welding, structuring and marking of all kind of materials. Molecular dynamics simulations contribute to new insight into the not completely comprehended ablation process with the short femto second laser pulses.

Experimental advancements within the last two decades have enabled unprecedented control of quantum systems, posing outstanding challenges for their theoretical description. Our project is based on a novel computational strategy at the intersection of machine learning and quantum physics, utilizing artificial neural networks to efficiently represent quantum wave functions. By leveraging supercomputing resources from FZ Jülich and the Gauss Centre for Supercomputing, we have advanced the theoretical understanding of strongly interacting systems in two dimensions, including the first demonstration of the quantum Kibble-Zurek mechanism.

This project targets various central questions in modern astrophysics, including "What is the nature of dark matter?", "How do galaxies form and evolve?" and "Do we understand the extremes of the universe?". Dwarf galaxies provide a natural laboratory for confronting these questions as we will explain below. The formation of dwarf galaxies tracks an extreme situation in various ways. Dwarf galaxies are assumed to be the very first type of galaxy to form in the earliest Universe.

The aim of this project is to create a highly accurate cosmological, hydrodynamical simulation model that can produce extremely realistic representations of dwarf galaxies right into the centers, where dark matter models can be tested.

The IHPms21 project combined advanced computer simulations with experimental techniques to develop new materials for future microelectronics that are compatible with silicon technology. Using ab initio density functional calculations, the project helped interpret experimental results and guide further research. The team achieved three key outcomes: first, they explained why germanium surfaces behave differently depending on their orientation during graphene growth; second, they uncovered how multilayer hexagonal boron nitride (hBN) can grow from an inert gas, despite its chemical inactivity; and third, they analyzed photoemission spectra to reveal the presence of ultrathin β-Ga2O3 films on the surface of ZnGa4O4 crystals.

Membrane topology transformations – such as scission, fusion, and pore formation – are driven by membrane tension, curvature stress, and lipid dynamics, playing critical roles in exocytosis and organelle division. The final stage of cellular compartment division involves the scission of a highly constricted membrane neck. Using self-consistent field theory (SCFT), we explore the mechanisms of scission in single- and double-membrane neck structures.

 

The Earth is a dynamic system, various physical processes lead to deformations of the Earths surface or mass transport in its interior. Quantifying the changes with the help of measurements is a key task of geodesy, for instance to make signals attributed to climate change visible. For this, reference systems and reference surfaces are required. E.g. sea level rise refers to the so called Mean Sea Surface (MSS), or the geoid as an equipotential surface is required to show mass transport. The reference surfaces can be determined from hundreds of million measurements collected by satellites. Due to the characteristics of the collected data and the complexity of the surfaces, high performance computing is required for the numerical analysis

In July 2021, a devastating flood hit Central and Western Europe, causing severe damage, especially in the Ahr region in Germany. Researchers at the University of Bonn investigated the role of soil moisture in intensifying this extreme event. Using the JUWELS supercomputer at Forschungszentrum Jülich, they simulated varying soil moisture conditions to assess its impact on precipitation. The findings suggest that land surfaces contributed significantly to the heavy rainfall, with potential for even more precipitation under wetter soil moisture conditions. These insights can help to improve understanding of land-atmosphere interactions and disentangle drivers of extreme events.

Irradiation modeling is a crucial aspect of integrated photovoltaic (PV) system yield prediction and optimizations of the design and dimensions of PV systems. Shading models typically rely on high-resolution topography data that includes buildings and vegetation. However, the cost and limited availability of such data pose significant challenges. In this project, we took an innovative approach by considering an alternative source of topography data: maps. Specifically, we focused on the OpenStreetMap (OSM) due to its open-data availability. While maps cannot be directly used for irradiance modeling, we explored novel approaches to overcome this challenge.

Bulk metallic glasses (BMGs) are known to have remarkable mechanical properties, such as high tensile strength, elasticity, and yield strength, which surpass those of many crystalline and polycrystalline metals. These properties make BMGs highly promising candidates for applications requiring materials that can withstand high and complex mechanical stress. However, BMGs have drawbacks; they show strain softening, resulting in localized deformation in the form of shear transformation zones that later lead to the formation of shear bands. This strain-softening characteristic limits their broader application potential, as it can lead to surface defects and, ultimately, fracture.

Prof. Dr. Holger Gohlke and Jesko Kaiser investigated the binding of resensitizers in the nicotinic acetylcholine receptor as a potential treatment option for nerve agent poisoning. They identified a potential allosteric binding site, explaining the experimentally observed effect on the receptor. Based on these results, the researchers identified novel analogs with improved properties and new lead structures with improved affinity compared to MB327, potentially acting as new starting points to ultimately close the gap in nerve agent poisoning treatment.

Chiral amines, a group of small chemicals, are central building blocks to a variety of fine chemical products. These include agrochemicals and pharmaceuticals such as Sitagliptin, a potent drug used to treat type II diabetes. Accordingly, biotech and pharmaceutical companies are highly interested in the efficient and sustainable production of these compounds. A group of enzymes already in use to fill this need are Transaminases (TAs). In this project, Prof. Dr. Gohlke and Steffen Docter investigated the thermal unfolding behavior of two sets of TA variants of fold type I and IV families of PLP-dependant enzymes by simulating rigid cluster decompositions using Constraint Network Analysis (CNA).

The efficiency of any opto-electronic device, such as a solar cell, light emitting diode, or photodetector, is intrinsically linked to the nature of the electronic quantum states of the photoactive material. For a deeper understanding and targeted development of new devices, an improved theoretical description of bound electronic excitations, i.e., excitons and trions, is crucial.

The exponential scaling in computational cost when simulating quantum many-body systems poses a significant challenge to their understanding. Variational methods, that approximate the state of the quantum system using an ansatz function, promise to lower that computational cost while making no approximations about the interactions that occur in the system. A novel type of ansatz function, which we explore thoroughly in this project, uses neural networks to approximate the state of the system. As is usual in deep learning, we rely heavily on the use of GPUs during execution, thereby making the use of the JUWELS Booster Module a necessity.

Researchers from Heinrich Heine University Düsseldorf have investigated the interaction of high-intensity laser pulses with matter using particle-in-cell simulations. Their research has led to a novel mechanism for compact ion acceleration, a method to generate spin-polarized ion beams, and a potential path to probe quantum electrodynamics.

We are all made of atoms, different types of atoms, and different combinations of them, which, by their turn, are composed of a cloud of electrons and a nucleus. A nucleus contains at least one proton in its simplest form, the hydrogen atom. Comprehending the proton, the origin of its measured properties, like its mass and electric charge, and its structure is, thus, one of the most important endeavors of the physical sciences. How can we probe/see the proton and its structure?

In a breakthrough that could revolutionize particle accelerators, scientists have discovered how to better control high-energy electron beams using ultra-powerful lasers. This new understanding delves deep into the complex dance between intense laser pulses and the plasma they create, revealing the subtle mechanisms that influence electron beam stability.

Numerical sciences are experiencing a renaissance thanks to the spread of heterogeneous computing. The SYCL open standard unlocks GPGPUs, accelerators, multicore and vector CPUs, and advanced compiler features and technologies (LLVM, JIT), while offering intuitive C++ APIs for work-sharing and scheduling. The project allowed for the kick-off of DPEcho (short for Data-Parallel ECHO), a SYCL+MPI porting of the General-Relativity-Magneto-Hydrodynamic (GRMHD) OpenMP+MPI code ECHO, used to model instabilities, turbulence, propagation of waves, stellar winds and magnetospheres, and astrophysical processes around Black Holes, in Cartesian or any coded GR metric.

 

Currently, the DRESDYN experiment is under construction. It aims to find and understand the mechanisms behind the excitation of a magnetic field due to the precessing motion of a conducting fluid. Such a precessing fluid is, for example, inside the core of the Earth, which is believed to sustain the Earth's magnetic field. To study the flow fields as well as the magnetic fields and to predict optimal parameter regimes for the DRESDYN experiment, numerical simulations are performed on JUWELS CPU using the code SpecDyn.

Periodically driven ultracold atomic systems can be used to engineer topologically nontrivial phases, and can give rise to anomalous topological phases with chiral edge modes in the presence of a trivial bulk (AFTI). We have investigated the role of additional quenched disorder and two-particle interactions on this state. Within an exact diagonalization study we have found signatures of the anomalous Floquet Anderson insulator (AFAI) phase within an experimentally realized model by calculating several indicators [1]. It supports quantized charge pumping through chiral edge states, while the bulk states remain completely localized. Moreover, we have developed an efficient new algorithm for calculating higher-order Chern numbers [2].

The internal structure of the proton and neutron (collectively known as the nucleon), which form the building blocks of atomic nuclei, still poses many open questions. Not only is it not completely understood how the nucleon’s spin and momentum are composed of those of its constituent particles (the quarks and gluons), but even its size is subject to significant uncertainty arising from discrepancies between different determinations: there is a decade-old inconsistency between the electric charge radius of the proton as obtained from scattering experiments in good agreement with the value from hydrogen spectroscopy on the one hand, and the most accurate determination from the spectroscopy of muonic hydrogen on the other. This significant…

Life at the molecular level is driven by the interplay of many biomolecules. Much like man-made machines in everyday life, they need to move, rotate, react to signals or use and provide resources. Unlike man-made machines, however, they function at the atomic level so directly observing their workings is impossible as they are invisible both to the naked eye and regular optic microscopes. Specific highly specialised equipment can provide insight into the inner working of these atomic-sized machines, but such equipment is very expensive and the required wet-lab setups can be highly involved.

High-mass star formation is a highly complex and dynamic process involving a large number of physical mechanisms. To better interpret real-world star-forming regions, simulations of collapsing clouds are used. These simulations produce the distribution of matter within star-forming regions, taking into account the effects of gravitational contraction as well as the feedback from massive stars. These simulations are then used to compute synthetic telescope images which may be compared to observations made with instruments like the Atacama Large Millimeter Array (ALMA).

Near field cosmology is the theoretical and observational study of our neighbourhood in the universe. This is the main topic of focus for the CLUES collaboration (www.clues-project.org). Our neighbourhood is the best observed part of the universe where also tiny dwarf galaxies can be studied. The properties of these dwarfs reflect their early formation history and state of the universe at the Cosmic Dawn, when the first stars and galaxies formed. Studying them sheds new light on these times, known as Cosmic Dawn and Epoch of Reionisation.

FitMultiCell is a computational pipeline developed by Prof. Dr.-Ing. Jan Hasenauer's team to tackle the complexity of simulating and fine-tuning biological tissues. This tool streamlines the creation, simulation, and calibration of biological models that imitate cellular interactions within tissues. The pipeline offers a user-friendly platform for researchers to conduct analyses on supercomputers like JUWELS. FitMultiCell's flexibility and power are demonstrated in studies on viral infections, tumor growth, and organ regeneration, proving its efficiency in refining models to match experimental data. Furthermore, enhancements for handling data outliers and scalability ensure FitMultiCell's robust application in diverse research fields.

In project CHMU14, challenging three-dimensional simulations of thermonuclear explosions of white dwarf stars near the Chandrasekhar-mass limit were conducted. These were followed by radiative transfer simulations that allow to predict observables. A comparison with astronomical data shows that such models can explain the subclass of Type Iax supernovae.

Although MD is a widely used and accepted method, there is often the need of comparison to experiment to validate the reliability of the findings. The development of supercomputers as well as the optimization of the used simulation code led to enormous changes in the achievable dimensions. Nevertheless, the simulation of an aluminum cube of 1 µm side length would contain about 60 billion atoms. To simulate this for a duration of 1 µs simulated time, with time step 1 fs, it would take 47,248 core years on a Cray XT5 system, based on the 1.49e-6 sec/atom/time step determined at the benchmark on the LAMMPS webpage [2].

The regular ups and downs of tides are phenomena obvious to any observer of the sea. Less known is that ocean tides also undergo small changes over time, for reasons that are not yet fully understood. In this project, large simulations with a global three-dimensional ocean model were performed to understand the extent to which ocean warming and the resultant increase in the vertical density structure have contributed to changes in the largest tidal wave, M2, from 1993 to 2020. Evidence was found that upper ocean warming is the leading cause for present weakening of the size of M2 across entire ocean basins. In turn, more tidal energy is currently being transferred from M2 to three-dimensional waves in the ocean’s interior.

Collisions of protons and pions are usually observed and measured in particle accelerators. Thanks to today’s powerful supercomputers we can study these elementary particles also in theory, namely based on the core principles of Quantum Chromodynamics. By simulating the fundamental quark and gluon fields on a space-time lattice not only can we investigate why protons (and pions and many other particles) emerge at all from the strong force, but also their reaction with each other, for example in an elastic collision. And sometimes such collisions bring forth entirely new, short-lived particles, like the Δ resonance. Our project is dedicated to applying the Lattice QCD method to track from fundamental quarks and gluons to the Δ particle.

Geothermal energy is vital for renewable power and heating. To improve project safety and efficiency, scientists employ various methods to understand subsurface processes. Monitoring earthquakes is key and reveals how the subsurface reacts to different factors. However, interpreting seismic recordings is challenging due to complex interactions and background noise. Underground processes are complicated by fluids and fault systems. Our project uses computer simulations to analyze seismic waves, enhancing our ability to pinpoint small earthquakes accurately. This helps understanding seismic triggers and reducing hazards. Additionally, we utilize recorded background noise to directly investigate subsurface structures, maximizing data insights.

Supersonic, magnetised turbulence is ubiquitous in the interstellar medium of galaxies. Unlike incompressible turbulence, supersonic turbulence is not scale-free. The scale that marks the transition from supersonic to subsonic turbulence is the so-called sonic scale, which in the context of star formation may define the critical value for which regions inside of molecular gas clouds collapse under their own gravity to form stars.

Gallium oxide (Ga2O3), a transparent semiconducting oxide with a wide bandgap of around 4.9 eV, has emerged as a promising candidate for future applications in electronics (Schottky barrier diodes, field-effect transistors), optoelectronics (solar- and visible-blind photodetectors, flame detectors, light emitting diodes, touch screens), and sensing systems (gas sensors, nuclear radiation detectors) [2]. The monoclinic β phase is its most stable and studied polymorph. Compared to the bulk properties, research on its surface properties is still sparse. However, these play a crucial role in many processes and applications, such as epitaxial growth and electrical contacts.

 

Ammonia (NH3) is a versatile compound that finds applications in fertilizer production and fiber manufacturing. The industrial synthesis of ammonia relies on high temperatures and pressures, and requires large amounts of energy while emitting greenhouse gases. A more promising alternative is the electrochemical nitrogen reduction reaction (NRR), which offers a more efficient and environmentally friendly way for ammonia synthesis. Researchers from Technical University of Munich (TUM) have taken this concept further by utilizing artificial-intelligence methods to theoretically design and screen appropriate catalysts for the NRR process. These catalysts, known as single-atom catalysts, play a crucial role in facilitating the reaction.

The project "High performance computational homogenization software for multi-scale problems in solid mechanics" focusses on simulating Advanced High-Strength Steels (AHSS) using computational methods that consider the microscale grain structure. The virtual laboratory relies on high-performance computing and robust numerical methods to predict steel behavior before experimental testing. Computational homogenization reduces the number of degrees of freedom drastically and introduces natural algorithmic parallelism. The scalability of new nonlinear solution methods, as well as the FE^2 software FE2TI was demonstrated under production conditions. A complete virtual Nakajima test was performed leveraging the power of modern supercomputers.

More food for a growing human demand needs more water to produce it. Nevertheless, global water resources are limited. Without appropriate action towards a most efficient and most sustainable water use, the world will run into a severe water crisis.

In the BMBF research project ViWA we show how High Performance Computing using SuperMUC-NG can open new ways to create the necessary knowledge for action towards more efficient and sustainable water use in agriculture. Complex global crop growth simulations based on climate and environmental data show how water could globally be saved through better farm management. Comparing simulations with actual global crop growth observations using Sentinel-2 satellites create a global monitoring system,…

Halide perovskites are booming as absorber materials for solar cells: they are cheap and easy to make in the lab while delivering devices with efficiencies of converting the energy of sunlight into electricity. An interesting, more fundamental aspect of these materials regards their atomic motions, which are unusual compared to other solar materials. Researchers at the Technical University of Munich used the power of the JUWELS cluster to investigate the impact of these atomic motions on the absorption of sunlight in halide perovskites. Their findings were intriguing: the strong atomic motions do not hinder but are in actuality a beneficial feature for the efficient collection of sunlight in halide perovskites.

Heinrich Heine University Researchers use JUWELS to study reactive metabolites in their pursuit of new biotechnological applications.

A research team led by Prof. Dr. Holger Gohlke at the Heinrich Heine University of Düsseldorf is a long-time user of the Jülich Supercomputing Centre’s (JSC’s) world-class high-performance computing infrastructure. The team has recently employed JSC’s JUWELS supercomputer to study a select class of enyzmes that play an outsized role in metabolizing chemical compounds coming from outside the body.

Controlled and reversible opening and forming of chemical bonds allows to switch material properties by light or mechanical load. The controlled change of material properties to enable different functionalities is a promising route to the design of so-called programmable materials that allow the tailored control of materials functions by well-defined external stimuli. A system that can reversibly form and break bonds is the molecule anthracene. Two anthracene molecules can bind together upon stimulation by UV-light. Heating in turn leads to the release of the formed bonds and thus to the regeneration of the initial state. Here we show that mechanical forces considerably accelerate this backreaction and do not lead to irreversible bond…

The MIQS project aims at uncovering demanding orbital-based mechanisms in quantum materials driven by strong electron correlation. First-principles many-body approaches are employed to tackle the challenging electronic states in systems such as superconducting nickelates and layered van der Waals magnets. Complex electronic phases are explored on a realistic level by combining density functional theory and dynamical mean-field theory methods on an equal footing. The high computational power of the JUWELS is needed to address the intriguing many-body physics subject to a large number of degrees of freedom at different temperature scales. Predictions and fathom design routes for novel materials and architecture is an essential part of the…

Due to a warming atmosphere and ocean, accelerated melting of the Greenland ice sheet and glaciers contribute increasingly to global sea level rise. We investigate this effect by reproducing observed sea level, temperature and salinity of the northern North Atlantic Ocean in a numerical ocean model. We compared different model simulations to situ observations and satellites data. Adding realistic Greenland melting results in a better model agreement with data, especially in Baffin Bay. Our study suggests that further work should focus on improving model resolution souch that small-scale processes can be well represented.

It has been a long-standing dream in nuclear physics to study nuclei like, for instance, carbon directly from Quantum Chromodynamics (QCD), the underlying fundamental theory of strong interactions. Such an endeavor is very challenging both, methodically and numerically. Towards this goal physicists from the European Twisted Mass Collaboration and in particular the University of Bonn have investigated two- and three-hadron systems using the approach of Lattice QCD.

A research team at the Heidelberg Institute for Theoretical Studies and Heidelberg University is using the power of high-performance computing (HPC) to better understand how collagen—the most common protein in our body—transports shock and other forces toward its weakest molecular links, giving researchers deeper insight into understanding how collagen in tendons absorbs stress and how this can prevent larger injuries

A research team led by Prof. Szabolcs Borsányi, long-time users of Gauss Centre for Supercomputing (GCS) resources, have leveraged GCS’s world-class computing resources in pursuit of furthering our understanding of the most fundamental building blocks of matter and their respective roles in how the universe came to be.

A research team based at the University of Wuppertal has benefited from generous shares of Gauss Centre for Supercomputing (GCS) resources. Participating in many consortia involved in gaining a fundamental understanding of the universe’s most basic building blocks, the team combines numerical theory with experiment in pursuit of a richer understanding of how the universe and all that is in it came to be.

With the help of world-class supercomputing resources from the Gauss Centre for Supercomputing (GCS), a team of researchers led by Prof. Zoltan Fodor at the University of Wuppertal has continued to advance the state-of-the-art in elementary particle physics.

A research team led by Prof. Holger Gohlke at the Heinrich Heine University Düsseldorf is using supercomputing resources at the Jülich Supercomputing Centre (JSC) to better understand so-called hyperpolarization-activated cyclic nucleotide–gated (HCN) channels, which serve as crucial ion channels in the membrane for controlling electric pulses in the brain and heart, among other fundamental processes in the body.

Particle accelerators are among the world’s most effective methods for experiments in materials science and physics. High-intensity, laser-based accelerators are novel accelerator-concepts which are much more compact compared to conventional accelerator facilities. As next-generation facilities with even more powerful lasers begin to come online, researchers must reckon with how these devices can alter plasmas contained in these accelerators through so-called quantum electrodynamic (QED) effects. Researchers predicted how lasers in these facilities would behave, and researchers are now leveraging high-performance computing (HPC) to model these QED effects and compare with experimental data.

A team of researchers led by Dr. Denis Wittor at the University of Hamburg has been leveraging the high-performance power of the JUWELS supercomputer at the Jülich Supercomputing Centre (JSC) for deeper insight into radio relics, cloud of diffuse radio wave emission, often found in galaxy clusters.

Using HPC resources at the High-Performance Computing Center Stuttgart, a team led by Prof. Britta Nestler is improving sintering—a common process in advanced manufacturing.

Using the JUWELS supercomputer at the Jülich Supercomputing Centre, researchers are simulating the so-called Brout-Englert-Higgs mechanism, or how elementary particles acquire mass.

For decades, researchers have turned to the twin power of state-of-the-art particle accelerator facilities and world-class supercomputing facilities to better understand the mysterious world of subatomic particles. These particles are very short lived and are hard to detect with even the most advanced technologies. In recent years, researchers have used the Large Hadron Collider at CERN, among other facilities, to discover new charmed baryons.

Using the JURECA supercomputer, a team of University of Cologne researchers led by Prof. Dr. Joseph Kambeitz is simulating biophysical processes in the brain in pursuit of better understanding what leads to schizophrenia in patients. 

Researchers at the Ludwigs-Maximillians Universität München are focused on studying the concentration of galaxies called the Coma, which is made up of more than 1,000 galaxies in our interstellar neighborhood. Using experimental facilities and world-class computng, the team was able to simulate the Coma cluster in unprecedented detail.

A research team led by Prof. Dr. Holger Gohlke and Dr. Carlos Navarro-Retamal have been using the JUWELS supercomputer at the Jülich Supercomputing Centre (JSC) to better understand how plants respond to changes in their environment at a molecular level. Specifically, the team used JUWELs to simulate how the TPC protein—also prevalent in the human body—helps facilitate information sharing between different parts of a plant in responding to changes in temperature, light, or other conditions that can affect growth. In order to gain a fundamental understanding of the process, the researchers ran computationally intensive molecular dynamics simulations of up to 600,000 atoms.

A team of researchers led by Prof. Dr. Holger Gohlke and Till El Harrar have been using high-performance computing (HPC) resources at the Jülich Supercomputing Centre (JSC) to better understand how aqueous ionic liquids and seawater interact with enzymes relevant for a host of biotechnological applications. Recently, the team focused on how aqueous ionic liquids—reminiscent to molten salts, certain types of mineral-rich hydrothermal waters and the like—impact behavior of the enzymes Lipase A from Bacillus subtilis. The team published three papers on its research.

A team of researchers led by Prof. Xiaoxiang Zhu at the Technical University of Munich are using high-performance computing resources at the Leibniz Supercomputing Centre to create the first-ever 3D/4D dataset on urban morphology of settlements, joining traditional remote sensing data with social media content.

Polymers are a broad class of materials: From nylon and rubber to materials for advanced material design, polymers are long chains of repeating units. Diblock copolymers consist of two halves that repel each other and self-assemble into different phases, creating shapes such as cylinders at the molecular scale. These cylinders arrange as parallel within an individual grain but, on large scales, there are multiple grains that differ in the orientation of their cylinders.

A group of researchers from the Fritz Haber Institute and Aarhus University in Denmark have leveraged the power of the JUWELS supercomputer at the Jülich Supercomputing Centre (JSC) to develop a machine learning algorithm that helps predict how specific molecules bind to the surface of a catalyst. Catalysts play an essential role in many chemical processes, and how specific molecules interact with these materials can influence the efficiency, effectiveness, and safety of chemical reactions at an industrial scale.

A research team led by Prof. Frithjof Karsch at Bielefeld University has been using the JUWELS supercomputer at the Jülich Supercomputing Centre (JSC) as part of the international HOTQCD collaboration to better understand the conditions under which particles made of protons, neutrons, and pions go through phase transitions, and how those changes impact the system’s behavior and give rise to new forms of matter, such as quark-gluon plasma.

Using high-performance computing (HPC) resources at the Jülich Supercomputing Centre, a team of researchers led by Technical University of Dortmund Professor Frithjof Anders is gaining a better understanding of electrons’ behaviors in so-called quantum dots.

In this long term project, which lasted for 6 years and had two stages, we computed the leading order hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon, aLO−HVP, using lattice quantum field theory.

Simulations at the atomic level employing supercomputers are a powerful instrument to probe and design new materials or understand better already known ones. Such findings and discoveries could potentially lead to new landscapes regarding the usage of our planet’s resources. Here we present results of our quantum-mechanical simulations investigating the band gap properties of silicon (Si) and germanium (Ge) alloys with cubic and tetragonal symmetries. These alloys’ investigations were inspired by their synthesis using high pressure techniques.

Quarks are the constituents of the massive basic building blocks of visible matter. These building blocks are the hadrons, more precisely protons and neutrons, which are about 2,000 times heavier than electrons. It was a heroic effort to determine the nature of the phase transition for physical quark masses, which our group carried out in 2006 and published in Nature. This finding has fundamental consequences for the early universe and for the possible remnants we might detect even today. Note however, the result has not only relevance for the early universe (Big Bang) but also for heavy ion collisions (Little Bang), which are carried out at the RHIC (Brookhaven, USA) and LHC (Geneva, Switzerland) accelerators.

Zinc ions have shown antiviral properties, but a key issue for their use for antiviral therapy is its difficulty, as a divalent metal ion, to cross the cell membrane and thus reach its targets inside the cell. A variety of ligands, including the FDA approved drug chloroquine (CQ), form complexes with these ions have been proposed to assist zinc permeation, possibly promoting the combined beneficial action of both zinc ions and the drugs against the virus. Here, we studied the permeation of chloroquine and the interaction of the drug with zinc ions in aqueous solution. For the latter, we take advantage of highly scalable ab initio molecular dynamics simulations to explore the diverse coordination chemistry of zinc ions.

The defining properties of our numerical research in the domain of correlated electron systems are the notions of emergence and criticality. Emergence only occurs in the thermodynamic limit where the volume of the system is taken to infinity at constant particle number. To investigate this phenomena we use the Algorithms for Lattice Fermion implementation of the auxiliary field quantum Monte Carlo algorithm that allows to simulate a large variety of model systems on importance in the solid state.

 

Complex magnetic textures and localized particle-like structures on the nanometer scale such as chiral magnetic skyrmions with non-trivial topological properties are nowadays the most studied objects in the field of nanomagnetism. They offer the promise of new data storage and data processing technologies ranging from racetrack memories to memristive switches for neuromorphic computing. In this project we extend the realm of DFT calculations for magnetic systems to significantly larger setups from the basic description provided by our ab-initio code FLEUR

Our Cosmic Home, which is the local volume of the Universe centered on us, contains very prominently visible structures, extending over almost one billion light-years. Such structures, ranging from the Local Group over the Local Void and the most prominent galaxy clusters like Virgo, Perseus, Coma and many more, represent a formidable site where extremely detailed observations exist. Therefore, cosmological simulations of the formation of galaxies and galaxy clusters within the Local Universe, rather than any other, randomly selected part of the cosmic web, are perfect tools to test our formation and evolution theories of galaxies and galaxy clusters down to the details. However, at these detailed levels, such simulations are facing various…

In high-precision low energy particle physics experiments, small but significant discrepancies have been found when compared to expectations from theory. This has substantially increased the interest in precision nucleon structure measurements. Theoretically, strong interaction phenomena are governed by Quantum Chromodynamics (QCD), and at energy scales relevant to the proton structure, the only known way of studying QCD from first principles is via large scale simulations using the lattice formulation.

Gravitational wave detectors such as LIGO, VIRGO, and KAGRA, have brought about an era of multi-messenger astronomy that has given new insights into the merger of binary compact objects. In all cases, the ability to constrain the characteristics of the compact objects is very limited, especially in the absence of an electro-magnetic (EM) counterpart. Gravitational wave events such as GW190425, however, present a very unique opportunity to study the mass gap regime where the binary could consist of either a black hole and a neutron star (BHNS) or a highly asymmetric neutron star binary (BNS).

Quantum Chromodynamics (QCD) is the sector of the standard model describing the strong nuclear force, which binds quarks and gluons inside hadrons. The theory confines these constituents, which are never observed directly in experiment. In this project the researchers study charmonium, a system containing a charm quark-anti-quark pair.

G-protein coupled receptors (GPCRs) are membrane proteins that transmit the effects of extracellular ligands to effect changes in the intracellular G-protein signaling system. Approximately 800 GPCRs are encoded in the human genome and approximately half of all marketed drugs target GPCRs. Crystal structures often deviate from the natural system: Proteins, especially membrane-bound ones, do not necessarily crystallize in their biologically active structures and the measures needed to obtain suitable GPCR crystals tend to increase the diversity between the natural environment and the crystal. It is within this context that molecular-dynamics simulations play a special role in GPCR research as a full-value complement to experimental studies.

The amazing progress in observational cosmology over the last decades has brought many surprises. Perhaps the most stunning is that we live in a Universe where most of the matter (~85%) is comprised of yet unidentified collisionless dark matter particles, while ordinary baryons produced in the Big Bang make up only a subdominant part (~15%). The real physical nature of dark energy, as well as the mass of the neutrinos which contribute a tiny admixture of “hot” dark matter, are profound and fundamental open questions in physics. To make further progress, this firmly established standard cosmological model will be subjected to precision tests in the coming years that are far more sensitive than anything done thus far.

Space is the finest plasma laboratory one can reach, hence many of the fundamental and universal physics discoveries of to the fourth state of matter – plasma – root to space physics. The near-Earth space is the only place one can send spacecraft to study the variability of plasma ranging from meters to millions of kilometres and from milliseconds to hundreds of years. However, one can send only a few satellites on a few orbits, making near-Earth space environment modelling crucial. To model the near-Earth space accurately, one requires a good resolution for the 3D position space, and additional 3D space for particle distributions— demanding computing performance that easily can reach the limits of any available supercomputer. 

Solution crystallization and dissolution are of fundamental importance for science and industry. In this project, molecular dynamics simulations were used to study these processes at the molecular scale. By following the motion of molecules towards and away from the crystal surface over short periods of time the intrinsic kinetic behavior that governs the growth and dissolution can be extracted. The obtained information is then used for parametrization of other methods such as kinetic Monte Carlo and continuum simulations to study the dynamics of the crystal surface from the nanoscale up to the microscale and beyond, where the theoretical results would be industrially relevant and easily comparable to experimental results.

This ongoing project aims at investigating the long-term evolution of a merging binary system of two neutron stars. The investigation conducted within this project is well aligned with the past research conducted by the Relastro group in Frankfurt and is motivated by the gravitational-wave detection GW170817 and its electromagnetic counterpart, the
so-called kilonova. This kilonova signal is produced by the nuclear processes within the dense and neutron rich mass that is ejected during the merger. Since a lot of mass is ejected during the longterm postmerger evolution, it is crucial to investigate this part via state-of-the-art simulations in order to fully understand the observation.

Leveraging the computing power of HPC systems SuperMUC and SuperMUC-NG hosted at LRZ, researchers of the Munich University of Applied Sciences investigated the piezoelectric properties of ferroelectric hafnia and zirconia, which represent a novel material class based on the fluorite crystal structure. If properly doped, such thin films show large strain effects in field induced phase transitions. A large number of doped supercells were investigated with density functional theory to find the most appropriate dopants.

Clouds and precipitation are the major source of uncertainty in numerical predictions of weather and climate. A common analysis of polarimetric radar observations and synthetic radar data from numerical simulations provides new methods to evaluate models. Using the Terrestrial Systems Modeling Platform, researchers conducted ensemble simulations for multiple summertime storms over north-western Germany. The simulated cloud processes were compared in the radar space using a forward operator with the measurements from X-band polarimetric radars. In addition, sensitivity studies were conducted using different background aerosol states and land cover types in the model to better understand land-aerosol-cloud-precipitation interactions.

Geological processes are generally quite complex and occur under a wide range of thermodynamic conditions. The structure and the properties of crystalline and non-crystalline phases in the Earth’s interior are often not accessible directly and must be investigated by experiments and by numerical simulations. In this project, we use predictive molecular simulation approaches to establish relations between structural properties of relevant phases, in particular oxide and silicate glasses and melts and aqueous fluids, at high temperatures and high pressures and their respective thermodynamic and physical properties.

Most biological functions are mediated by conformational changes and specific association of protein molecules. Atomistic simulations are ideal to study the molecular details of such systems. However, often the associated timescales are beyond the maximum simulation times that can be reached even on supercomputers. In this project, researchers developed and tested advanced sampling simulations to accelerate protein domain motions and association of partner molecules. These techniques allow to study domain motions and association of protein molecules on currently accessible time scales. They were successfully applied to study the Hsp90 chaperone protein and to several protein-protein and protein-peptide systems of biological importance.

The conformations of ubiquitin chains are crucial for the so-called ubiquitin code, i.e. the selective signaling of ubiquitylated proteins for different fates in the eukaryotic cellular system. Extensive molecular dynamics simulations at two resolution levels were carried out for ubiquitin di-, tri- and tetramers of all possible linkage types. Analyzing the resulting, exceedingly large high-dimensional data sets was made possible by combining highly efficient neural network based dimensionality reduction with density based clustering and a metric to compare conformational spaces. The so obtained conformational characteristics of ubiquitin chains could be correlated with linkage-type and chain-length dependent experimental observations.

In the framework of the ASCETE (Advanced Simulation of Coupled Earthquake and Tsunami Events) project, the computational seismology group of LMU Munich and the high performance computing group of TUM jointly used the SuperMUC HPC infrastructures for running large-scale modeling of earthquake rupture dynamics and tsunami propagation and inundation, to gain insight into earthquake physics and to better understand the fundamental conditions of tsunami generation. The project merges a variety of methods and topics, of which we highlight selected results and impacts in the following sections.

The ExaHyPE SuperMUC-NG project accompanied the corresponding Horizon 2020 project to develop the ExaHyPE engine, a software package to solve hyperbolic systems of partial differential equations (PDEs) using high-order discontinuous Galerkin (DG) discretisation on tree-structured adaptive Cartesian meshes. Hyperbolic conservation laws model a wide range of phenomena and processes in science and engineering – together with a suite of example models, an international multi-institutional research team developed two large demonstrator applications that tackle grand challenge scenarios from earthquake simulation and from relativistic astrophysics.

Quantum Chromodynamics (QCD) is the theory of strong interactions. It explains how quarks and gluons form the composite particles called hadrons which are observed in nature. Hadrons can be studied by means of computer simulations of QCD discretized on a Euclidean lattice. This project focuses on hadrons formed by heavy quarks. The question addressed is the relevance of including virtual charm-quark effects in lattice QCD simulations. This dynamics is challenging since it requires small values of the lattice spacing for reliable extrapolations to zero lattice spacing. It is found that its effects are at the sub-percent level even for quantities like the decay constants of charmonium at an energy scale of about half of the proton mass.

Researchers investigated the formation and evolution of molecular clouds, i.e. the nurseries of star formation, by means of 3D magneto-hydrodynamical simulations. These molecular clouds, which are embedded in a galactic disk like our Milky Way, were modelled with a high spatial resolution using a smart zoom-in approach relying on the adaptive mesh refinement technique. As the modelled molecular clouds were embedded in a realistic astrophysical environment, it was possible to study their detailed evolution, e.g. the impact of supernova explosions and radiation from nearby massive stars. Moreover, the research team modelled the chemical evolution of these clouds as well as their dynamics and complex internal structure.

Today, large-scale computations of lattice QCD can easily reach a precision of 1% and below—a level at which it is necessary to factor in isospin breaking arising from 1. the presence of the electromagnetic interaction, and 2. the mass difference between up and down quarks. The most prominent consequence of these effects is the mass difference of the neutron and the proton as its numerical value influences the stability of matter: were this difference a bit different from what is measured in experiments, matter would become unstable so that no atoms, molecules and more complex structures could be formed. It was successfully demonstrated that this mass difference can be computed in a common lattice framework of a full QCD + QED calculation.

Investigating hadron structure, how the quark and gluon constituents account for the properties of hadrons (which include neutrons and protons), is challenging due to the nature of the strong interaction. However, such information is crucial for exploiting experiments that are searching for evidence of the physics that lies beyond our current understanding of particle physics (that is encapsulated in the Standard Model) as these experiments often involve protons and neutrons in some way. Hadron structure observables can be computed via large-scale numerical calculations. This project determines key quantities on a fine lattice with physical quark masses, enabling reliable results to be extracted.

Understanding the response of silicon and diamond to shear deformation is crucial to improve the performance of nanodevices and low friction coatings. Atomic length scale simulations show that the two materials differ significantly in their amorphization-mediated wear behavior: Externally applied pressure favors the wear of silicon, while it reduces the wear of diamond. For silicon, a shear-induced recrystallization process opposes amorphization. By choosing suitable orientations of two silicon crystals in the sliding contact, the combination of both phase transformations can be exploited to grow silicon crystals with nanoscale precision.

Synthetic or biological amphiphiles self-assemble into spatially modulated structures on the nanoscale with applications ranging from etch masks in semiconductor fabrication, over porous membranes for separation or energy applications, to the compartmentalization of living cells. Often, such systems do not reach thermal equilibrium but, instead, the structures are dictated by processing and kinetic pathways. These molecular simulations provide insight into the correlation between molecular structure and collective dynamics that alter the self-assembly. Two results are being highlighted: (i) the kinetically accessible states in the course of directed self-assembly and (ii) the kinetic pathway of the fusion of two apposing lipid membranes.

Before the first stars formed more than 13 billion years ago, the gas of the Universe consisted of hydrogen, helium, and lithium only. Elements necessary for life, eg carbon or oxygen, are produced by stars, and it is of fundamental importance to understand how the first stars formed. With a large allocation on SuperMUC and SuperMUC-NG, state-of-the-art numerical simulations were performed to mimic these first star formation regions. In these high-resolution simulations, two effects – a so-called Lyman-Werner background and streaming velocities – that delay star formation globally were included. It could be demonstrated for the first time that the combination of both effects results in an even more delayed formation of the first stars.

To understand solar and stellar magnetic field evolution combining local and global numerical modelling with long-term observations is a challenging task: even with state-of-the-art computational methods and resources, the stellar parameter regime remains unattainable. Our goal is to relax some approximations, in order to simulate more realistic systems, and try to connect the results with theoretical predictions and state-of-the-art observations. Higher resolution runs undertaken in this project will bring us into an even more turbulent regime, in which we will be able to study, for the first time, the interaction of small- and large-scale dynamos in a quantitative way.

The project developed multiscale 3+1D simulations of binary neutron mergers in numerical general relativity for applications to multi-messenger astrophysics. It focused on two aspects: (i) the production of high-quality gravitational waveforms suitable for template design and data analysis, and (ii) the investigation of merger remnants and ejecta with sophisticated microphysics, magnetic-fields induced turbulent viscosity and neutrino transport schemes for the interpretation of kilonova signals. The simulations led to several breakthroughs in the first-principles modeling of gravitational-wave and electromagnetic signal, with direct application to LIGO-Virgo's GW170817 and counterparts observations. All data products are publicly released.

Focused ion beams can be used to pattern 2D materials and ultimately to create arrays of nanoscale pores in atomically thin membranes for various technologies such as DNA sequencing, water purification and separation of chemical species. Among 2D materials, transition metal dichalcogenides, and specifically, MoS2, are of particular interest due to their spectacular physical properties, which make them intriguing candidates for various electronic, optical and energy conversion applications. Findings achieved by running large-scale molecular dynamics simulations to study the response of MoS2 monolayer to cluster ion irradiation suggest new opportunities for the creation of 2D nanoporous membranes with an atomically thin nature.

Metal hydrides have become of great scientific interest as high-temperature superconducting materials at high pressure, with hydrogen-hydrogen interactions suspected as critical in this behavior. Here, nuclear magnetic resonance experiments and electronic structure calculations are combined to explore the compression behavior of FeH and Cu2H, and results show that within the hydrides a connected hydrogen network forms at significantly larger H-H distances than previously assumed. The network leads to an increased contribution of hydrogen electrons to metallic conduction, and seems to induce a significantly enhanced diffusion of protons.

At high temperatures the nuclear matter melts into a plasma state. This phase transition is expected to have a “critical point” for systems which have increasingly more protons than antiprotons. The search for this elusive critical point on the QCD phase diagram is one of the greatest challenges in today’s high energy physics, both in theory and in experiment. The calculations of the theory at non-zero densities in supercomputers are hampered by the sign-problem. In this project multiple research tracks were pursued and the methods that deal with the sign-problem and search for signals of the critical point on the phase diagram were developed.

Protons are composite particles: bound states of quarks and gluons, as described by the theory of quantum chromodynamics (QCD). Using lattice QCD, we know in principle how to use supercomputers to compute various properties of the proton such as its radius and magnetic moment, however this is very challenging in practice. A major part of this project was devoted to developing and studying methods for more reliable calculations, in particular for obtaining more accurate results in a finite box and for better isolation of proton states.

As most notorious greenhouse gas, CO2 emissions prevail as high as about 364 million tons carbon with the concentration reaching over 400 ppm in the atmosphere. A drastic reduction of CO2 is urgently necessary for sustainable growth and to fight climate change. The electrochemical reduction of CO2 (CO2RR) is a promising approach to utilize renewable electricity to convert CO2 into chemical energy carriers at ambient conditions and in small-scale decentralized operation. Researchers from Technical University of Munich have employed an active-site screening approach and proposed carbon-rich molybdenum carbides as a promising CO2RR catalyst to produce methanol.

A multi-institutional team of researchers is developing a data assimilation framework for coupled atmosphere-land-surface-groundwater models. These coupled models, which potentially allow a more accurate description of the coupled terrestrial water and energy fluxes, in particular fluxes across compartments, are affected by large uncertainties related to uncertain input parameters, initial conditions and boundary conditions. Data assimilation can alleviate these limitations and this project is focused in particular on the value of coupled data assimilation which means that observations in one compartment (e.g., subsurface) are used to update states, and possibly also parameters, in another compartment (e.g., land surface).

GPCRs sit in the cell membrane and transmit signals from the outside of the cell to its interior. Currently, drugs targeting these receptors only work by mimicking ligands, i.e. they activate or inhibit the receptors by changing their conformation. If the GPCR adopts an active conformation, it can bind proteins on the intracellular side of the cellular membrane, which then transmit the signal inside the cell. In this study, we investigated how a protein that stops the GPCR from signaling, interacts with a prototypical GPCR. We discovered that specific lipids can modify how signals are transmitted by modifying the way of interaction between the GPCR and arrestin. In the future this could enable the discovery of a new kind of drugs for GPCRs.

MPIA scientists have developed a planetesimal formation model based on high-resolution hydro-dynamical simulations performed on JSC HPC systems. The simulations were used to model disk turbulence and its two effects on the dust, the mixing and diffusion of the dust on large scales but also the concentration of dust on small scales. This research helped to better understand the efficiency of these processes and to derive initial mass functions for planetesimals and gas giant planets to predict when and where planetesimals and Jupiter-like planets should form and of which size they will be. This is a fundamental step forward in understanding the formation of our own solar system as well as of the many planetary systems around other stars.

In this project the most inner structure of the proton has been deciphered through a large-scale numerical simulation of quantum chromodynamics. This could be achieved by novel algorithms developed by the project team. In particular, the project made a large leap forward to solve the spin puzzle of the proton. While theory predicted a dominant contribution to the spin of the proton from the quarks, in experiments it was found that this contribution is surprisingly small. The research team found out that it is actually the gluon which is contributing a large fraction of the spin. Although still a number of systematic uncertainties have to be fixed, this is a most remarkable result which will lead to eventually resolve the proton spin puzzle.

In this project, the biophysics of Photosynthesis are probed employing high-performance computing. Photosynthesis is based on the Sun light and fuels the metabolic pathways of numerous organisms in our biosphere. However, fluctuations in the light intensity or quality are expected due to the diurnal cycle, or the environmental conditions and could be detrimental to plants. Absorption of light and tunnelling of the associated energy towards the reaction centres of the photosynthetic apparatus are finely-tuned within a well-orchestrated photoprotective mechanism. The atomic-scale details of this mechanism is probed by computational biophysics, with applications on the increase of crop yields and artificial photosynthesis.

It is well-known that the catalytic properties of metals may extend beyond their melting point. Recently, this has been exploited to grow high-quality 2D materials such as graphene. To improve our understanding of the growth mechanism on liquid metal catalysts, researchers at the Technical University of Munich have employed a multi-scale modelling approach. Here, detailed simulations of various building blocks for the final graphene sheet such as simple hydrocarbons and smaller graphene flakes on solid and liquid Cu surfaces have been carried out. The insights from these simulations were then used to propose a mesoscopic model for the dynamics of graphene growth on molten Cu based on capillary and electrostatic interactions.

Computational fluid dynamics (CFD) simulations play an important role in today’s science and technology. Therefore, it is crucial to validate its underlying methods and models. This can be done by experiments or with molecular dynamics (MD) simulations, but in some cases only the latter are applicable. Since MD simulations follow the motion of each molecule individually, they are computationally very demanding, but they rest on an excellent physical basis. In this project, large systems of several hundred million atoms are considered to study the thermo- and hydrodynamic behavior of fluids during shock wave propagation, droplet coalescence and injection. The results are compared to that of macroscopic numerical methods.

Super-Yang-Mills theory is a central building block for supersymmetric extensions of the Standard Model. While the weakly coupled sector can be treated within perturbation theory, the strongly coupled sector must be dealt with a non-perturbative approach. Lattice regularizations provide such an approach but they break supersymmetry and hence the mass degeneracy within a supermultiplet. Researchers of Uni Jena study N=1 supersymmetric SU(3) Yang-Mills theory with a lattice Dirac operator with an additional parity mass. They show that a special 45° twist effectively removes the mass splitting at finite lattice spacing–thus improves the continuum extrapolation—and that the DDαAMG algorithm accelerates such lattice calculations considerably.

The Universe was just a few microseconds old when the gradually cooling matter organized itself into the massive particles that form much of the visible matter today, protons and neutrons. The fascinating world of the hot Universe is recreated in huge particle accelerators. These experiments go beyond the study of the primordial world, as they can probe a whole new dimension by tuning the balance of particles vs antiparticles. This imbalance, the net baryon density, could be tuned to the extreme, as that can be found in neutron stars. Researchers of Uni Wuppertal launched a large scale simulation project to calculate how baryon density impacts temperature where today's particles emerge from the primordial plasma.

The outer layers of the Sun are convectively unstable such that heat and momentum are transported by material motions. These motions are thought to be responsible for the large-scale magnetism and differential rotation of the Sun. Employing a more realistic description of the heat conductivity in our simulations than in previous studies, we demonstrate that stellar convection is highly non-local. Furthermore, we found substantial formally stably stratified but fully mixed layers that can cover up to 40 per cent of the solar convection zone. These results are reshaping our picture of stellar convection.

A supramolecular polymer (SMP) has functional groups which interact with each other to form a physical bond. In contrast to chemical bonds, the bond formation in an SMP is reversible and the resulting aggregate morphology in a SMP melt thermally fluctuates. For functional groups allowing only a pairwise association, a ring aggregate is highly important as a ring topologically reduces the mobility of surrounding linear polymers by threading. Using molecular dynamics simulations of SMPs, the effect of ring aggregates on the system relaxation time governing rheological response was investigated. It was shown that the presence of ring aggregates slows down rheological response as measured by a reduction of the so-called entanglement length.

Heat shock protein 90 (Hsp90) is a molecular chaperone essential for the folding and stabilization of a wide variety of client proteins in eukaryotes. Many of these processes are associated with cancer and other diseases, making Hsp90 an attractive drug target. Hsp90 is a highly flexible protein that can adopt a wide range of distinct conformational states, which in turn are tightly coupled to the enzyme’s ATPase activity. In this project, atomistic molecular dynamics simulations, free energy calculations, and hybrid quantum mechanics/classical mechanics simulations were performed on both monomeric and full-length dimeric Hsp90 models to probe how long-range effects in the global Hsp90 structure regulate ATP-binding and hydrolysis.

The nucleon has an extremely complicated many-body wave function because QCD is very strongly coupled, very non-linear and characterized by massive quantum fluctuations. Its investigation started with collinear processes and has by now progressed to non-collinear ones. The latter are characterized by non-trivial parallel transport, leading to observable effects. Many of these are described by TMDs the properties of which are not yet well understood and are planned to be studied at the new Electron Ion Collider. We have calculated one of the most important of these properties on the lattice. Only in 2020, first lattice calculations, all using alternative approaches, of this quantity were published. All results agree within error.

The SuperMUC-NG is being used to simulate materials from first-principles, materials ranging from active materials important to technology to planetary materials that govern, for example, Earth’s magnetic field. Solid and liquid iron at conditions of Earth’s core have been simulated, and transport properties such as electrical and thermal conductivity were computed to constrain the properties that govern Earth’s dynamo. At much lower pressures, filled ices, which are believed to form in the interior of water planets such as Titan, and carbon solubility in silicates melts in the mantle of the Earth were studied. Three new class of materials were developed computationally: polar metallocenes, ferroelectric clathrates, and polar oxynitrides.

The hot and dilute astrophysical plasmas - from Solar to galactic scales - are inherently turbulent. The turbulence determines transport and structure formation in accretion disks, in the interstellar medium, in clusters of galaxies as well as their observable radiation. Due to its routing in microscopic kinetic processes the turbulence of astrophysical plasmas is, however, not well understood, yet. Utilizing state-of-the-art microphysics particle-in-cell codes in this project self-consistent 3D electromagnetic kinetic simulations were performed to simulate the kinetic turbulence inherently linked with two fundamental processes of energy conversion in the Universe – collisionless shock waves and magnetic reconnection.

Generating high energy ions by irradiating an ultra-intense laser pulse on a foil-coated foam-like double-layer plasma target is investigated with the help of particle-in-cell simulations. The foil is ultra-thin so that the incident laser pulse can penetrate through it. The acceleration of ions happens in the foam when the density of the foam is in the laser-induced relativistic-transparent regime. Simulations show that a proton beam with peak energy beyond 150 MeV is generated by using a 16 Joule laser pulse. The laser pulse used in the simulation is already available, and the targets can be prepared with the current technology. This simulation work provides helpful information for the further experiments and related applications.

The African Continent will be severely hit by climate change. A necessary building brick for counteraction are reliable projections of the African climate of our century. The CORDEX CORE initiative is designed to provide such information for the CORDEX CORE regions, among them CORDEX CORE Africa. IMK-TRO contributed to this with an ensemble of presently ten regional climate simulations performed on the Hazel Hen at HLRS Stuttgart. Results indicate dramatic changes especially in precipitation. The simulations presented here will be part of the IPCC AR6 atlas of regional climate change and the CORDEX data repository. They will be freely available for impact, adaptation and mitigation studies.

Complex I is the largest and most intricate respiratory enzyme, which couples the free energy released from quinone reduction to transfer protons across a biological membrane. Recent X-ray structures of bacterial and eukaryotic complex I have advanced our understanding of the enzyme’s function, but the mechanism of its long-range energy conversion remains unsolved. Here, we use atomistic molecular dynamics simulations and free energy calculations to study how the protonation state, hydration dynamics, and conformational dynamics of complex I regulate its proton pumping activity. Our simulations mimic transient states in the enzyme’s pumping cycle to draw a molecular picture of the protonation signals along the membrane domain of complex I.

Quantifying the dynamics of basins across diverse time and space scales is one challenge faced by earth scientists. To understand their response to natural or man-made forcing is crucial to constrain the state and fate of georesources and hazards related to their exploitation. In this project, we developed and used a hybrid scalable modelling approach combining deterministic and probabilistic modules to improve our comprehension of the complex nonlinear dynamics of this specific terrestrial compartment interacting with the other geo-hydro-atmosphere systems making up the system Earth.

Lattice QCD enables calculation of many details of quark-gluon bound states like the proton. One first parameterizes all properties of, e.g., the proton by certain parameters and functions. Next, one links experimental observables to these quantities and clarifies their meaning. In recent years, lattice calculations have become a valid alternative to performing experiments to determine these quantities. We have calculated the quantity d2, which characterizes certain spin-dependent effects and is linked to the color force exerted on quarks in a proton or neutron. Non-trivial renormalization properties make this an especially difficult quantity to calculate, but this project was successful in doing so with results that agree with experiment.

Core-collapse supernovae are among the most energetic events in the Universe and can be as bright as a galaxy. They mark the violent, explosive death of massive stars, whose iron cores collapse to the most exotic compact objects known as neutron stars and black holes. In this project self-consistent 3D simulations with state-of-the-art microphysics were performed for the explosion of a ~19 solar-mass star, whose final 7 minutes of convective oxygen-shell burning had been computed, too. It could be demonstrated that explosions by the neutrino-driven mechanism can produce powerful supernovae with energies, radioactive nickel ejecta, and neutron-star masses and kick velocities in agreement with observations, in particular Supernova 1987A.

Recent cosmological observations tell us that only a small part of the matter content of the Universe is coming from ordinary particles, e.g. protons and neutrons. We call the rest dark matter. But what constitutes this invisible ingredient of the Universe? A possible candidate is the so called axion, for which a mass limit was worked out in the prequel of this project. To learn more on the features of this hypothetical particle its dynamics was investigated through a link to the strong interactions.

Core-collapse supernovae are among the most energetic events in the Universe and can be as bright as a galaxy. They mark the violent, explosive death of massive stars, whose iron cores collapse to the most exotic compact objects known as neutron stars and black holes. In this project self-consistent 3D simulations with state-of-the-art microphysics were performed for the explosion of a ~19 solar-mass star. It could be demonstrated that muon formation in the hot neutron star, which had been ignored in supernova models so far, leads to a faster onset of the explosion. The effects of muons thus over-compensate the delay of the explosion caused by low resolution, where numerical viscosity impedes the growth of hydrodynamic instabilities.

The FirstLight project at LRZ is a large database of numerical models of galaxy formation that mimic a galaxy survey of the high-redshift Universe, before and after the Reionization Epoch. This is the largest sample of zoom simulations of galaxy formation with a spatial resolution better than 10 pc. This database improves our understanding of cosmic dawn. It sheds light on the distribution of gas, stars, metals and dust in the first galaxies. This mock survey makes predictions about the galaxy population that will be first observed with future facilities, such as the James Webb Space Telescope and the next generation of large telescopes.

The availabiltiy of ultra-short, high-power lasers has led to greater interest in their potential use for accelerators, as the charge separation in plasmas can induce enormous electromagnetic field strengths on a sub-micrometer scale. With the high performance and extreme scalability of the Plasma Simulation Code (PSC) for fully kinetic simulations, a wide field of applications was researched: From ions for medical purposes (Ion Wave Breaking Acceleration and Mass-Limited Targets) to breakthrough Lepton acceleration by proton-driven wakefields (AWAKE), all the way to radiation generation (attosecond X-ray pulses from Ultra-Thin Foils). Even QED based approaches were covered in this project.

Although Quantum Chromodynamics (QCD) has long been established as the correct theory of the subatomic strong interaction, obtaining quantitative predictions from it often represents a challenging computational task. In this project, large-scale lattice QCD simulations are used to determine structural properties of protons and neutrons. The lattice approach to QCD amounts to discretizing space-time and applying importance-sampling techniques to the path-integral representation of QCD. One specific observable under scrutiny in this project is the “scalar matrix element” of the proton, which provides a quantitative answer to the question of “How much would the proton mass change if the light quark masses changed by a small amount?”.

To unravel the complexity of the solid state, researchers from the University of Würzburg have mastered very different and complementary methods. Density functional theory in the local density approximation with added dynamical local interactions using the dynamical mean-field approximation has the merit of being material dependent since one can include the chemical constituents of materials. Spacial and temporal fluctuations are crucial to understand e.g. the Iridates, a topic that is explored with the new pseudo-fermion functional renormalization group. Another aspect of this research are realistic quantum Monte Carlo simulations of free standing graphene aiming to elucidate the role of electronic correlations.

Two major events are responsible for what is considered the “golden age” of relativistic astrophysics. One is the detection of gravitational waves from merging neutron stars heralding the beginning of the multimessenger age. The other is the effort of the Event Horizon Telescope collaboration culminating in the first image of a black hole. Both events have been aided by simulations that require HPC. With this project, several studies could be conducted well alligned with these type of simulations expanding our knowledge about these important astrophysical events.

The Standard Model of Particle Physics is a highly successful theoretical framework for the treatment of fundamental interactions, but fails to explain phenomena such as dark matter or the abundance of matter over antimatter. Precision observables, such as the anomalous magnetic moment of the muon, aμ, play a central role in the search for “New Physics”. A promising hint is provided by the persistent tension of 3.7 standard deviations between the theoretical estimate for aμ and its experimental determination. In our project we employ the methodology of lattice QCD to compute the hadronic contributions to aμ from first principles. In the long run, our results will supersede the estimates based on data-driven approaches and hadronic models.

To avoid dangerous climate change, we have to reduce the emission of greenhouse gases radically. This requires – among other measures – an increase of renewable sources of energy like solar and wind. In 2019, already a quarter of Germanys electricity demand has been met by wind power. In order to increase this share, one has to develop sites in hilly terrain. High resolution models are required to assess the suitability of candidate sites with respect to turbulence intensity, power production and variability. This project supports the development of the test-site WINSENT, which is located on the Swabian Alp near Stuttgart.

The water electrolysis in Proton Exchange Membrane (PEM) cells is fitting plenty of industrial requirements. The main drawback of PEM cells however is the overpotential of the oxygen evolution reaction. In its acidic environment iridium dioxide (IrO2) is currently the only stable catalyst. Yet the low abundance of iridium makes a reduction of its loading inevitable. One approach to decrease the catalyst loading is the use of nanoparticles. For catalyst optimization a general understanding of shape and surface structure of these nanoparticles is required. In this project a protocol has been developed to generate and simulate IrO2 nanoparticles based on energies of slab models and to provide insights regarding stability and structure.

Neutron stars are ultracompact stars in which densities above the nuclear saturation densities are reached and that provide one of the best laboratories to test nuclear physics principles. Within this project, researchers perform 3+1-dimensional numerical-relativity simulations studying the last few orbits before the merger of two of these stars. In fact, a binary neutron star merger is one of the most energetic phenomena in our Universe and is accompanied by a variety of electromagnetic signatures and with characteristic gravitational-wave signatures. With the help of these simulations existing theoretical models can be developed and verified and the growing field of multi-messenger astronomy is supported. 

Carbon nitride materials have attracted vast interest in the field of photocatalytic water splitting. However, the underlying mechanism is not fully understood. Herein, results are being reported from large-scale first-principles simulations for the specific electron- and proton-transfer processes in the photochemical oxidation of liquid water with heptazine-based photocatalysts. The results reveal that heptazine possesses energy levels that are suitable for the water oxidation reaction. Moreover, the critical role of the solvent in the overall water-splitting cycle is shown. A simple model is developed to describe the water oxidation mechanism.

Cells communicate with each other through biochemical as well as mechanical signals. Essential biological processes such as cell division are critically steered by the tension across the cell-cell contacts. Using extensive molecular dynamics simulations, scientists analyzed the underlying molecular principles of mechano-sensing at cell-cell contacts. These simulations can give first insights into how proteins present at the cell-cell contact change their structure and localization and thereby help to sense mechanical stimuli. The findings can help understanding the mechanisms by which tissues, e.g. skin, grow along the direction of pulling forces which were applied by adding virtual springs into the simulation system.

The general interest of the researchers of this project is in disordered thin film superconductors within the Boguliubov-deGennes (BdG) theory of the attractive-U Hubbard model in the presence of on-site disorder; the sc-fields are the particle density n(r) and the gap function ∆(r). For this case, system sizes unprecedented in earlier work are being reached. They allow to study phenomena emerging at scales substantially larger than the lattice constant, such as the interplay of multifractality and interactions, or the formation of superconducting islands. For example, it is being observed that the coherence length exhibits a nonmonotonic behavior with increasing disorder strength already at moderate interaction strength.

Using the vast computing power of the HPC system JUWELS of JSC, an international team of physicists – the HotQCD Collaboration – simulates almost massless quarks and reveals another piece in the puzzle of how hot quarks and gluons behave under extreme thermal conditions.

High-energy ion-beam therapy of tumours has many advantages compared with conventional radiation therapy. Ion beams generated by synchrotron accelerators have been used in many medical institutions. However, a synchrotron accelerator has a large footprint (soccer field size) and is expensive. With the rapid development of high power laser technology, a laser-plasma ion accelerator is a more compact (table-size) and inexpensive alternative. Ion wave breaking acceleration which happens in laser-driven foam-like plasma targets is a promising regime for designing controllable high-energy high-quality ion accelerators. To gain a deeper knowledge on it, researchers carried out 3D simulations on SuperMUC using the Plasma-Simulation-Code (PSC).

The approximately 800 G-protein coupled receptors (GPCRs) in the human genome regulate communication across cell walls. They are targeted by approximately 40% of all marketed drugs. The project uses molecular-dynamics (MD) simulations to investigate ligand binding and receptor activation processes in GPCRs. An activation index for Class A GPCRs has been developed from a series of µsec molecular-dynamics simulations and tested for 275 published X-ray structures.  Binding of the α-domain of G proteins to GPCRs has also been characterized in detail. Metadynamics simulations in conjunction with unbiased MD simulations demonstrated the effect of mutations on the GPCR-ligand interaction in the histamine H1 receptor.

Roughness of many natural and engineered surfaces follows a scaling law called self-affine scaling. In project chka18, the origins of self-affine have been investigated using Molecular Dynamics simulations. It was shown that the self-affine roughness emerges naturally during deformation of initially flat surfaces in different materials.

Numerical models are excellent tools to improve our understanding of atmospheric processes across scales since they provide a consistent 4D representation of the atmosphere. Project WRFSCALE consists of different sub-projects, applying the Weather Research and Forecasting (WRF) model at resolutions between 3 km and 100 m, performing investigations in the fields of data assimilation, bio-geoengineering and boundary layer research. By increasing the resolution to 100 m, the model starts to explicitly resolve the representation of turbulence. With such simulations and comparisons to high-resolution observations, it is the aim to better understand the turbulent boundary layer and its interaction with the underlying land surface.

The Atlantic Meridional Overturning Circulation transports warm tropical surface water towards northern Europe and returns cold water at depth to the world’s ocean. At the same time it plays a significant role in the global carbon cycle through the ocean’s ability to dissolve carbon dioxide. This overturning is thus of great climatic importance, but a complete picture of its driving forces has not yet emerged due to several observational and theoretical challenges. Using realistic coarse and high resolution ocean models, scientists investigated the ocean response to changes in wind stress and the ability of meso-scale eddy parameterisations to simulate that response.

In nuclear fusion experiments, researchers routinely heat hot gases up to temperatures of 100 million degrees in order to create the conditions needed for energy-producing fusion reactions. Turbulence is one of the main obstacles on the way to sustaining these conditions reliably. A particular challenge is found in the plasma edge, where turbulence is suppressed by a self-organized transport barrier. Researchers from the Max-Planck Institute for Plasma Physics have made important progress to understanding the turbulence in this region, leveraging resources provided by the Gauss Centre for Supercomputing.

Understanding the internal structure of the nucleon is an active field of research with important phenomenological implications in high-energy, nuclear and astroparticle physics. Nucleon structure functions and their derivatives, parton distribution functions (PDFs) and generalized parton distribution functions (GPDs), teach us how the nucleon is built from quarks and gluons, and how QCD works. Beyond that, the cross section for hadron production at the LHC relies upon a precise knowledge of PDFs.

Within this project, the goal is to study and develop novel approaches to boost the performance of thin film solar cells. For this, 3D optical simulation of the photovoltaic devices is performed by discretizing Maxwell’s equations. A sophisticated light management is important to construct thin-film solar cells with optimal efficiency. The light management is based on suitable nano structures of the different layers and materials with optimized optical properties. The design, development and test of new solar cell prototypes with respect to an optimal light management are time consuming processes. For this reason, suitable models and simulation techniques are required for the analysis of optical properties within thin-film solar cells.

The proteasome is a large biomolecular complex responsible for protein degradation. Recent experimental data revealed that there is an allosteric communication between a core and regulatory parts of the proteasome. In the project, researchers have used atomistic simulations to study molecular details of the allosteric signal – in their study triggered by a covalent inhibitor. While the inhibitor causes only subtle structural changes, the proteasome-wide fluctuation changes may explain the self-regulation of the biomolecular machine.

Using HPC system resources available at the Jülich Supercomputing Centre, scientists of the Institute for Theoretical Physics of the Goethe-Universität in Frankfurt/Germany are performing extensive simulations to theoretically predict the properties of the phase transition from nuclear matter to a quark gluon plasma state.