# Latest Projects (Overview)

Find out about the latest simulation projects run on the GCS supercomputers. For the complete overview of projects, sorted by research fields, please choose from the list in the left column.

## High-Resolution Ocean Modelling on Unstructured Meshes

Results from high-resolution simulations with the sea ice-ocean model FESOM, formulated on unstructured meshes, are presented in which ocean eddies are resolved in the North Atlantic region. By resolving ocean eddies, these features are represented by the laws of physics rather than empirical rules of thumb, as done in most existing climate simulations. A comparison with satellite data suggests that the simulated eddy fields start to become indistinguishable from observations, showing that the model passes the climatic Turing Test. It is argued that these high-resolution resolution models have the potential to significantly increase our understanding of how the climate in general and the ocean in particular will be evolve in a warming world.

**Principal Investigator:** Prof. Dr. Thomas Jung, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), (Germany)

**HPC Platform:** Hazel Hen (HLRS) -** Date published: **January 2019* (GCS-AWCM)*

**More: High-Resolution Ocean Modelling on Unstructured Meshes …**

## Large Eddy Simulations of Micro-Vortex Generators for Shock Wave/Turbulent Boundary Layer Interaction

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.

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

**HPC Platform:** JUQUEEN (JSC) -** Date published: **January 2019* (PRA097)*

**More: Large Eddy Simulations of Micro-Vortex Generators for Shock Wave/Turbulent Boundary Layer Interaction …**

## Towards Large-Eddy Simulation of Primary Atomization of Liquid Jets

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.

**Principal Investigators:** Markus Klein and Sebastian Ketterl, Institute of Mathematics and Applied Computing, Bundeswehr University Munich (Germany)

**HPC Platform:** SuperMUC (LRZ) -** Date published: **January 2019* (pr48no)*

**More: Towards Large-Eddy Simulation of Primary Atomization of Liquid Jets …**

## Robust Massively Parallel Sorting

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.

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

**HPC Platform:** JUQUEEN (JSC) -** Date published: **December 2018* (hka17)*

**More: Robust Massively Parallel Sorting …**

## The ClimEx Project: Investigating Climate Variability to Study Extreme Events in a Warming World

Hydrometeorological extremes, such as droughts and floods are one of the grand challenges of our future and pose great interest and concern for water management and public safety. Hence, the ClimEx project disaggregates the response of the climate system into changing anthropogenic forcing and natural variability by analyzing a novel large-ensemble of climate simulations, operated using High-Performance Computing. The comprehensive new dataset (CRCM5-LE) generated 50 transient independent and evenly likely realizations of the past and the future climate (1950-2099) over two large domains (Europe, Eastern North America) in high spatial (12km) and temporal (1h-1d) resolution. The resulting 7500 model years allow for a thorough analysis of extreme statistics and derivation of robust estimates of return values for hydrometeorological extreme events (e.g. floods) under current and future climate conditions.

**Principal Investigator:** Ralf Ludwig, Ludwig-Maximilians-Universität München (Germany)

**HPC Platform:** SuperMUC of LRZ - **Date published:** December 2018* (pr94lu)*

**More: The ClimEx Project: Investigating Climate Variability to Study Extreme Events in a Warming World …**

## Highly-Resolved Numerical Simulation of Combustion in Energy Conversion Processes

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.

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

**HPC Platform:** Hazel Hen (HLRS) -** Date published: **December 2018* (Cnoise)*

**More: Highly-Resolved Numerical Simulation of Combustion in Energy Conversion Processes …**

## Viscosity Estimate with Staggered Fermions

Lattice QCD has played a crucial role in the determination of the true equation of state. It is a numerical approach to solve the theory of strong interactions, quantum chromodynamics (QCD), which provides first principles access to the physics of QGP. Lattice QCD assumes thermal equilibrium, where also the equation of state is defined. Researchers calculated this input to hydrodynamics in a succession of projects with the goal to investigate, whether such first principle determination of the (shear) viscosity parameter is possible from lattice QCD.

**Principal Investigator:** Szabolcs Borsanyi, University of Wuppertal (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date published: **December 2018 *(hwu30)*

**More: Viscosity Estimate with Staggered Fermions …**

## Direct Numerical Simulation of Turbulent Plane Couette Flow with Wall-normal Transpiration Velocity

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, new and unexpected structures close to the wall are observed in the spectra.

**Principal Investigator:** Martin Oberlack, TU-Darmstadt (Germany)

**HPC Platform:** SuperMUC of LRZ -** Date published: **December 2018* (pr92la)*

**More: Direct Numerical Simulation of Turbulent Plane Couette Flow with Wall-normal Transpiration Velocity …**

## Direct Numerical Simulation of Turbulent Flow Past an Acoustic Cavity Resonator

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 improve and simplify the design process.

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

**HPC Platform:** Hazel Hen of HLRS -** Date published: **Nov. 2018* (AcouTurb)*

**More: Direct Numerical Simulation of Turbulent Flow Past an Acoustic Cavity Resonator …**

## Colloids in Multiphase Flow

Particle-stabilised emulsions have long been studied for their unique properties, which have a number of different industrial applications. Leveraging the petascale computing power of JSC high-performance computing system JUQUEEN, scientists of the Eindhoven University of Technology have been using simulations to investigate these systems, the results of which are now being picked up by experimental groups and realised in practice.

**Principal Investigator:** Jens Harting, Eindhoven University of Technology (The Netherlands)

**HPC Platform:** JUQUEEN of JSC - **Date published:** November 2018* (COMFLOW)*

**More: Colloids in Multiphase Flow …**

## Enhanced Aerodynamics of Wind Turbines

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.

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

**HPC Platform:** SuperMUC of LRZ -** Date published: **November 2018* (pr94va)*

**More: Enhanced Aerodynamics of Wind Turbines …**

## Aerodynamic Investigations of Vortex Dominated and Morphing Aircraft Configurations with Active and Passive Flow Control

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.

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

**HPC Platform:** SuperMUC of LRZ - **Date published:** November 2018* (pr86fi)*

**More: Aerodynamic Investigations of Vortex Dominated and Morphing Aircraft Configurations with Active and Passive Flow Control …**

## Extreme-Scale Molecular Dynamics Simulation of Droplet Coalescence

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.

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

**HPC Platform:** Hazel Hen (HLRS) -** Date published: **October 2018* (GCS-mddc)*

**More: Extreme-Scale Molecular Dynamics Simulation of Droplet Coalescence …**

## The Search for the *H* Dibaryon in Lattice QCD

All visible matter around us is made from nuclei, each consisting of protons and neutrons. One of the triumphs of 20th century particle physics is the realisation that protons and neutrons are made from even smaller building blocks, the so-called quarks, which are now regarded as the fundamental constituents of matter. Particles such as the proton and neutron (collectively referred to as baryons) are considered bound states of three quarks. The theory of Quantum Chromodynamics (QCD) describes with very high accuracy the forces that act between these elementary building blocks. However, it remains a great challenge to provide a quantitative description of particles such as the proton and nuclear matter in terms of the underlying interaction between quarks. In this project scientists study bound states of two baryons (so-called dibaryons) as prototypes of more complex systems such as light nuclei. The formulation of QCD on a space-time grid is employed, which makes the theory amenable to a numerical treatment. More specifically, the focus is on the so-called *H* dibaryon, whose existence has been predicted 40 years ago. These studies show that such a state may actually exist.

**Principal Investigator:** Hartmut Wittig, Institute for Nuclear Physics and PRISMA Cluster of Excellence, Johannes Gutenberg University of Mainz (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date published: **October 2018 *(hmz21)*

**More: The Search for the H Dibaryon in Lattice QCD …**

## Binary Neutron Star Merger Simulations

The collision of two neutron stars is one of the most violent events in the Universe. The extreme conditions, with densities of about one hundred million tons per cubic centimeter and gravity hundred billion times that of Earth gravity, cannot be tested on Earth, which makes these events a perfect laboratory to study matter at extreme limits. Using advanced numerical relativity simulations, scientists study the phenomena close to the merger of the two neutron stars to extract information about the emitted gravitational wave and electromagnetic signals.

**Principal Investigator:** Tim Dietrich, Max Planck Institute for Gravitational Physics Potsdam (Germany)

**HPC Platform:** SuperMUC of LRZ - **Date published:** October 2018* (pr48pu)*

**More: Binary Neutron Star Merger Simulations …**

## Molecular Dynamics Simulations of Deformation Processes in Nanostructured Metallic Glasses

Metallic glasses are very strong and nonetheless elastic, making them appealing for diverse engineering applications. Despite these favourable properties, the failure of metallic glasses sets in directly after the elastic limit, making them brittle. In this project, scientists at the Technische Universität Darmstadt investigate nanostructured metallic glasses as a possible solution to this problem using large-scale molecular dynamics simulations.

**Principal Investigator:** Karsten Albe, Technische Universität Darmstadt (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date published:** October 2018* **(hda22)*

**More: Molecular Dynamics Simulations of Deformation Processes in Nanostructured Metallic Glasses …**

## Global, Convection-Permitting Climate Modelling with the Model for Prediction Across Scales in the WCRP CORDEX Flagship Pilot Study

Using the Model for Prediction Across Scales (MPAS), four years of climate simulations at convection-permitting resolutions where carried out using a variable 30-3km resolution mesh, transitioning the so-called gray zone of convection around 5-10km. The comprehensive data set generated following the protocol of the CORDEX Flagship Pilot Study (FPS) on convection-permitting climate simulations will allow the CORDEX-FPS community to study the added value of global, variable-resolution simulations down to convective scales over traditional approaches employing regional climate models and/or coarse horizontal resolutions.

**Principal Investigator:** Dominikus Heinzeller, Karlsruhe Institute of Technology, Institute of Meteorology and Climate Research, Garmisch-Partenkirchen (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date published:** October 2018* (hka19)*

**More: Global, Convection-Permitting Climate Modelling with the Model for Prediction Across Scales in the WCRP CORDEX Flagship Pilot Study …**

## From Electrons to Planets

Without its magnetic field, life on Earth’s surface is impossible, since the magnetic field screens us from deadly solar radiation. In order to gain a better understanding of the generation of Earth’s magnetic field and heat flow in the Earth--which is crucial for understanding Earth's history--scientists have performed large scale simulations of crystalline and liquid iron alloys at conditions of Earth’s core, up to 6000K and over 300 million atmospheres of pressure, and have computed the electrical and thermal conductivity. The computationally very intensive first-principles molecular dynamics simulations for fluids required more than 60 million core hours of computing time on SuperMUC.

**Principal Investigator:** Ronald E. Cohen, Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München (Germany)

**HPC Platform:** SuperMUC of LRZ - **Date published:** September 2018* (pr92ma)*

**More: From Electrons to Planets …**

## Preparing for the Imminent Detection of Gravitational Waves from Binary Neutron Stars

The age of multi-messenger gravitational wave astronomy has arrived. The simultaneous detection of gravitational and electromagnetic waves from merging neutron stars has illustrated the importance of having high resolution numerical relativity simulations, performed on SuperMUC, available to disentangle the complex interplay of nuclear physics, neutrino physics, and strong field gravity. Using these simulations, it is possible to study matter at densities unreachable with terrestrial experiments and determine the origin of the heavy elements in the universe.

**Principal Investigator:** Luciano Rezzolla, Institute for Theoretical Physics, Goethe University Frankfurt (Germany)

**HPC Platform:** SuperMUC of LRZ - **Date published:** September 2018* (pr62do)*

**More: Preparing for the Imminent Detection of Gravitational Waves from Binary Neutron Stars …**

## Global High-Resolution Earth Models - Generation and Assessment

Much of what one refers to as geological activity of the Earth arises from convective processes within the Earth’s mantle that transport heat from the deep interior of our planet to the surface. One of the major challenges in the geosciences is to constrain the distribution and magnitude of the resulting vast forces that drive plate tectonics. Mantle flow also provides boundary conditions - thermal and mechanical - to other key elements of the Earth system (e.g., geodesy, geodynamo/geomagnetism). This makes fluid dynamic studies of the mantle essential to our understanding of how the entire planet works. In a long-term effort, scientists at the Ludwig-Maximilians-Universität München strive for improved computational models of the Earth's deep interior. To assess the quality of the models against Earth observations (e.g., geologic information) they run inverse models to track mantle flow back into the past.

**Principal Investigator:** Hans-Peter Bunge, Geophysics Section, Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München (Germany)

**HPC Platform:** SuperMUC of LRZ - **Date published:** September 2018* (pr48ca)*

**More: Global High-Resolution Earth Models - Generation and Assessment …**

## Critical Collapse and the Dynamics of Strong Gravity

General relativity describes the gravitational interaction as the curvature of spacetime. This involves complicated partial differential equations, and consequently extreme scenarios can be treated only by numerical simulations. In this project spacetimes close to the critical threshold of black hole formation were evolved on SuperMuc. These computations were performed using bamps, a new massively parallel code for numerical relativity. The spacetimes constructed constitute the most extreme regime imaginable - that in which cosmic censorship itself may be violated and the black hole singularity could be seen by distant observers.

**Principal Investigators: **David Hilditch and Bernd Brügmann, Theoretisch-Physikalisches Institut, Friedrich-Schiller-Universität Jena (Germany)

**HPC Platform:** SuperMUC of LRZ - **Date published:** September 2018 *(pr87nu)*

**More: Critical Collapse and the Dynamics of Strong Gravity …**

## CARo – Computational Aeroacoustics of Rotors

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.

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

**HPC Platform:** Hazel Hen (HLRS) -** Date published: **July 2018* (CARo)*

**More: CARo – Computational Aeroacoustics of Rotors …**

## Numerical Simulation of Rotary Wing Aerodynamics, Aeroelasticity and Aeroacoustics (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.

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

**HPC Platform:** Hazel Hen (HLRS) -** Date published: **July 2018* (HELISIM)*

**More: Numerical Simulation of Rotary Wing Aerodynamics, Aeroelasticity and Aeroacoustics (HELISIM) …**

## Studying *Structure* to Understand *Function* in Phases of the Elements

“If you want to understand function, study structure” (F. Crick). In the case of carbon, the very different properties of graphite, diamond, and carbon nanotubes can then be traced to different atomic arrangements. The elements provide a fruitful field of study in general. There are fewer than 100 stable elements, and trends can be identified more readily than in alloys with infinitely many compositions. He we describe cluster, amorphous, and liquid phases of the group 15 elements bismuth and antimony using molecular dynamics simulations based on density functional theory.

**Principal Investigator:** Robert O. Jones, Forschungszentrum Jülich (Germany)

**HPC Platform:** JUQUEEN (JSC) - **Date published:** July 2018* **(hpg00)*

**More: Studying Structure to Understand Function in Phases of the Elements …**

## Planet Formation Through the Gravitational Collapse of Solids and Gas

Planetesimals are kilometre-sized planetary building blocks in the early solar system. Scientists pioneered a scenario in which turbulent concentrations of the icy and dusty material leads to sufficiently large densities in which self-gravity dominates over gas shear and tidal forces of the star. As a consequence, the material collapses spontaneously under its own weight into planetesimals. Therefore, the motion of many millions of particles in magneto-hydro-dynamically and particle driven turbulence and include the gravity among gas and particles are all simulated in one huge simulation. The goal is to link the observations of dust around young stars in a quantified way to an initial mass distribution of planetesimals.

**Principal Investigator: **Hubert Klahr, Max-Planck-Institut für Astronomie, Heidelberg (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date published:** July 2018 *(hhd19)*

**More: Planet Formation Through the Gravitational Collapse of Solids and Gas …**

## Linear-Scaling Transport Approach for Innovative Electronic Materials

Researchers elucidate the molecular doping of prototypical representatives for the class of molecular semiconductors. As n-type dopants, molecular radicals, closed-shell molecules and metal-organic species are compared. By using the HPC system SuperMUC, they simulate doping-induced states and compare the simulations with ultraviolet photoemission and inverse photoemission spectra. One challenge in the simulations is the necessary accuracy of the computation of the involved energies in the doping process, which requires ab initio approaches. In addition, the disordered material blends include many complex molecules whose charging states and charging energies need to be simulated by taking into account the blend’s dielectric properties and microscopic molecular arrangement.

**Principal Investigator:** Frank Ortmann, Technische Universität Dresden (Germany)

**HPC Platform:** SuperMUC (LRZ) - **Date published:** June 2018* **(pr84po)*

**More: Linear-Scaling Transport Approach for Innovative Electronic Materials …**

## Towards Exascale Simulations of Plasma Fusion Devices

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 hierarchical discretization scheme, so-called Sparse Grids, to overcome the current computational limits (number of discretization points per dimension and memory requirements). This way, it will be possible to enable high-resolution simulations, to ensure scalability of the simulations to future exascale computers and beyond, and even to be able to cope with faults and failures which will be more frequent for the next generation of supercomputers.

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

**HPC Platform:** Hazel Hen (HLRS) -** Date published: **June 2018* (exaHD)*

**More: Towards Exascale Simulations of Plasma Fusion Devices …**

## First Principles Multiscale Kinetic Modelling of Catalytic Reactions

Researchers at the Technical University of Munich study surface catalytic processes at a variety of scales, combining several different theoretical methods. They take into account the molecular scale of chemical reactions by first principles calculations of thermodynamic adsorption energies and kinetic reaction barriers. These calculations serve as input for mesoscopic models, which include the statistical interplay between the various chemical reactions and allow to predict macroscopic reaction rates and product selectivities. The work provides new insight into the mechanisms of catalytic reactions and gives important leads how to design improved catalyst materials.

**Principal Investigator:** Karsten Reuter, Lehrstuhl für Theoretische Chemie, Technische Universität München (Germany)

**HPC Platform:** SuperMUC (LRZ) - **Date published:** June 2018* **(pr94sa)*

**More: First Principles Multiscale Kinetic Modelling of Catalytic Reactions …**

## Direct Numerical Simulation of Turbulent Heat Transfer with a Supercritical Fluid

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 this accurate and reliable approach, one needs to resolve very fine spatial and temporal scales, which ultimately results in the requirement of high-performance computing.

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

**HPC Platform:** Hazel Hen (HLRS) -** Date published: **May 2018* (DNSTHTS)*

**More: Direct Numerical Simulation of Turbulent Heat Transfer with a Supercritical Fluid …**

## Petascale Computations for Atomic and Molecular Collisions: PAMOP and PAMOP2

An international group of scientists leverages high-performance computing to support current and future measurements of atomic photoionization cross-sections at various synchrotron radiation facilities, ion-atom collision experiments, together with plasma, fusion and astrophysical applications. In their work they solve the Schrödinger or Dirac equation using the *R-*matrix or *R-*matrix with pseudo-states approach from first principles. Cross-sections and rates for radiative charge transfer, radiative association, and photodissociation collision processes between atoms and ions of interest for several astrophysical applications are presented.

**Principal Investigator: **Alfred Müller, Institut für Atom- und Molekülphysik, Universität Giessen (Germany)

**HPC Platform:** Hazel Hen of HLRS - **Date published:** May 2018 *(PAMOP/PAMOP2)*

**More: Petascale Computations for Atomic and Molecular Collisions: PAMOP and PAMOP2 …**