Latest Results Gauss Centre for Supercomputing e.V.

LATEST RESEARCH RESULTS

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

Environment and Energy

Principal Investigator: Michael Bader(1), Alice-Agnes Gabriel(2), (1)Technical University of Munich, (2)Ludwig-Maximilians-Universität München

HPC Platform used: SuperMUC and SuperMUC-NG of LRZ

Local Project ID: pr45fi

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.

Computational and Scientific Engineering

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.

Environment and Energy

Principal Investigator: Michael Bader(1), Alice-Agnes Gabriel(2), (1)Technical University of Munich, (2)Ludwig-Maximilians-Universität München

HPC Platform used: SuperMUC and SuperMUC-NG of LRZ

Local Project ID: pr48ma

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.

Elementary Particle Physics

Principal Investigator: Francesco Knechtli, Bergische Universität Wuppertal

HPC Platform used: SuperMUC and SuperMUC-NG of LRZ

Local Project ID: pn56fo

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.

Astrophysics

Principal Investigator: Daniel Seifried, I. Physikalisches Institut, Universität zu Köln

HPC Platform used: SuperMUC and SuperMUC-NG of LRZ

Local Project ID: pr94du

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.

Elementary Particle Physics

Principal Investigator: Kálmán Szabó, University of Wuppertal and Forschungszentrum Jülich, Germany

HPC Platform used: JUWELS of JSC, SuperMUC and SuperMUC-NG of LRZ

Local Project ID: chfz04, pn56bu

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.

Computational and Scientific Engineering

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.

Computational and Scientific Engineering

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.

Elementary Particle Physics

Principal Investigator: Sara Collins, Institute for Theoretical Physics, University of Regensburg

HPC Platform used: SuperMUC-NG of LRZ

Local Project ID: pn34xo

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.

Materials Science and Chemistry

Principal Investigator: Michael Moseler, Fraunhofer IWM, Freiburg, and University of Freiburg

HPC Platform used: JUWELS and JURECA of JSC

Local Project ID: chfr09

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.

Computational and Scientific Engineering

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.

Computational and Scientific Engineering

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. 

Materials Science and Chemistry

Principal Investigator: Marcus Müller, Institute for Theoretical Physics, Georg-August University, Göttingen

HPC Platform used: JUWELS and JUWELS Booster of JSC

Local Project ID: chgu14

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.

Astrophysics

Principal Investigator: Anna Therese Phoebe Schauer, Zentrum für Astronomie, Universität Heidelberg

HPC Platform used: SuperMUC and SuperMUC-NG of LRZ

Local Project ID: pr53ka

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.

Computational and Scientific Engineering

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.

Astrophysics

Principal Investigator: Maarit Käpylä, Aalto University, Department of Computer Science, Astroinformatics Group, Finland, and Max Planck Institute for Solar System Research, SOLSTAR group, Germany

HPC Platform used: SuperMUC-NG of LRZ

Local Project ID: pn98qu

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.

Astrophysics

Principal Investigator: Sebastiano Bernuzzi, Bernd Brügmann, Friedrich-Schiller-Universität Jena

HPC Platform used: SuperMUC and SuperMUC-NG of LRZ

Local Project ID: pn56zo

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.

Computational and Scientific Engineering

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.

Materials Science and Chemistry

Principal Investigator: Mahdi Ghorbani-Asl, Institute of Ion Beam Physics and Materials Research Helmholtz-Zentrum Dresden-Rossendorf

HPC Platform used: Hazel Hen of HLRS

Local Project ID: PP18184458

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.

Computational and Scientific Engineering

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.

For a complete list of projects run on GCS systems, go to top of page and select the scientific domain of interest in the right column.