# Applications from Scientific Engineering

## Cavitation Phenomena in Diesel Injection Systems

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 cavitation erosion during early stages of the design is desirable.
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## High-Amplitude Fluctuations of Velocity and Temperature Gradients in Turbulent Convection

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.
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## Multiscale Modelling of Particles in Suspension

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.
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## Morphology–Transport Relationships for Packed Columns

By simulating fluid flow through computer-generated, confined sphere packings, a team of scientists from the Department of Chemistry at the Philipps-Universität Marburg correlate morphological parameters with transport coefficients.
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## Numerical Investigation of Complex Multiphase Flows With Lagrangian Particle Methods

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.
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## Direct Numerical Simulations of Impeller Driven Turbulence and Dynamo Action

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
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## Numerical Simulation of Aircraft Engine Related Two-Phase Flows

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.
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## Numerical Computation of Combustion Generated Noise with Direct Numerical Simulation

Scientists of a group of different institutions try to analyse in-depth the formation mechanism of noise generated from turbulent flames and to predict such noise radiations already during the development phase. HPC supercomputing resources serve as simulation platform for this project.
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## Comparison of Navier-Stokes-Fourier Equation and Grad's Moment Equation Solutions for Turbulence

Leveraging the computing power of GCS supercomputer JUQUEEN, scientists work on taking a first significant step towards the evaluation of extended gasdynamic models, such as e.g. the Grad 13 and the regularized Grad 13 equations, for the simulation and modeling of turbulent fluid motion.
**More: Comparison of Navier-Stokes-Fourier Equation and Grad's Moment Equation Solutions for Turbulence …**

## Prediction of Stability Limits of Combustion Chambers with Large Eddy Simulation (LES)

Using the HPC capabilities of HLRS Stuttgart, scientists of the Karlsruhe Institute of Technology applied a physical model to predict the resonance characteristics of real, damped combustion systems. The model is able to describe the resonant characteristics of a single Helmholtz resonator type combustor for different operation conditions and geometries.
**More: Prediction of Stability Limits of Combustion Chambers with Large Eddy Simulation (LES) …**

## PAdDLES: p-Adaptive Discretisations for Large Eddy Simulation in Industrial Geometry

Using the HPC capabilities of GCS, scientists assess a DGM (discontinuous Galerkin method) solver for scale-resolving simulations. The main goal of the solver is the evaluation of whether p-adaptive DGM can be used for fast and reliable LES of turbomachinery flows.
**More: PAdDLES: p-Adaptive Discretisations for Large Eddy Simulation in Industrial Geometry …**

## Transitions in Turbulent Rotating Thermal Convection

Scientists investigate the influence of temperature-dependent fluid properties (non-Oberbeck-Boussinesq effects) and rotation through direct numerical simulations for various fluids and a wide range of rotation rates to get closer to the understanding of realistic flows in nature and in engineering.
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## Simulation of the Unsteady Flow Around the Stratospheric Observatory For Infrared Astronomy (SOFIA)

To further improve the pointing stability and observation quality of the IR-telescope of an airborne stratospheric observatory, researchers investigate passive flow control methods by means of computational fluid dynamics simulations on HPC system SuperMUC of the LRZ Garching.
**More: Simulation of the Unsteady Flow Around the Stratospheric Observatory For Infrared Astronomy (SOFIA) …**

## Project HRPIPE, Direct Numerical Simulation of Pipe Flow at High Reynolds Numbers

Researchers from the Delft University of Technology used HLRS supercomputer Hermit to study turbulent pipe flow, which is--from an engineering point of view--one of the most important flow geometries because of its wide range of technical applications.
**More: Project HRPIPE, Direct Numerical Simulation of Pipe Flow at High Reynolds Numbers …**

## Direct Numerical Simulation of the Boundary Layers Transition and Interaction at the Entrance of a Plane Channel

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. Scientists used GCS supercomputers to study the turbulent transition of the boundary layers developing at the entrance of a plane channel.
**More: Direct Numerical Simulation of the Boundary Layers Transition and Interaction at the Entrance of a Plane Channel …**

## Numerical Simulations of a Supersonic Jet at High Reynolds Number with Turbulent Inflow Conditions

In a GCS Large Scale project, numerical simulations of a supersonic jet were performed on HPC system SuperMUC of LRZ, focusing on the research of the acoustic field.
**More: Numerical Simulations of a Supersonic Jet at High Reynolds Number with Turbulent Inflow Conditions …**

## Fathoming the Processes Inside Rocket Combustion Chambers

Researchers at the Institute of Combustion Technology for Aerospace Engineering (IVLR) at the University of Stuttgart use petascale system Hermit of HLRS for very detailed, three-dimensional simulations to realistically reproduce the essential processes in rocket combustion chambers like mixing of fuel and air, ignition and flame stabilization at supersonic conditions.
**More: Fathoming the Processes Inside Rocket Combustion Chambers …**

## Aircraft Wake Vortex Evolution During Approach and Landing With and Without Plate Lines

Computational fluid dynamics simulations executed on GCS system SuperMUC of LRZ Garching are used to investigate the complex vortex system detaching from the aircraft wings in high-lift configuration.
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## Hypersonic Boundary-Layer Transition

iA 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.
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## Li-Ion Batteries in Hybrid and Pure Electric Vehicles

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.
**More: Li-Ion Batteries in Hybrid and Pure Electric Vehicles …**

## Laminar-Turbulent Transition in Aerodynamics Boundary Layers

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).
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## Direct Numerical Simulation of the Flow in an Internal Combustion Engine

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.
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## Numerical Investigation of the Flow Field Around Delta Wings

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.
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## Project 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.
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## Ablation Process of Femto Second Laser Pulses

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.
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