Nagel / Resch High Performance Computing in Science and Engineering '09

Transactions of the High Performance Computing Center, Stuttgart (HLRS) 2009
1. Auflage 2010
ISBN: 978-3-642-04665-0
Verlag: Springer
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 551 Seiten, eBook

This book presents the state of the art in simulation on supercomputers. Leading researchers present results achieved on systems of the High Performance Computing Center Stuttgart (HLRS) for the year 2009. The reports cover all fields of computational science and engineering ranging from CFD to computational physics and chemistry to computer science with a special emphasis on industrially relevant applications. Presenting results for both vector systems and microprocessor-based systems the book allows comparing performance levels and the usability of various architectures. As HLRS operates the largest NEC SX-8 vector system in the world this book gives an excellent insight into the potential of vector systems. The book covers the main methods in high performance computing. Its outstanding results in achieving the highest performance for production codes are of particular interest for both scientists and engineers. The book comes with a wealth of coloured illustrations and tables of results.

Zielgruppe

Research

Autoren/Hrsg.

Resch, Michael

Nagel, Wolfgang E.

Inhaltsverzeichnis

Physics.- Numerical Models for Emission Line Nebulae in High Redshift Radio Galaxies.- The SuperN-Project: Current Advances in Understanding Core Collapse Supernovae.- Using Computational Steering to Explore the Parameter Space of Stability in a Suspension.- Solid State Physics.- Adsorption of Cysteine on the Au(110)-surface: A Density Functional Theory Study.- Characterization of Colloidal IV-VI Semiconductor Quantum Dots.- Understanding Long-range Indirect Interactions Between Surface Adsorbed Molecules.- H Carrying Capacity by Considering Charging and Discharging Processes – Case Studies on Small Carbon- and Boron Nitride Nanotubes.- Molecular Dynamics Study of Plastic Deformation of Nanocrystalline Palladium.- Conductance of Correlated Nanostructures.- Chemistry.- How do Eigenfunctions of Douglas-Kroll Operators Behave in the Vicinity of Point-like Nuclei?.- Distributed Memory Parallelization of the Multi-Configuration Time-Dependent Hartree Method.- Development of Models for Large Molecules and Electrolytes in Solution for Process Engineering.- Reacting flows.- Numerical Characterization of a Gas Turbine Model Combustor.- Numerical Investigations of NO-Formation in Scramjet Combustors.- Large-Eddy Simulation of Lean Premixed Flames in a Model Swirl Burner.- Computational Fluid Dynamics.- Higher Order Adaptive and Parallel Simulations Including Dynamic Load Balancing with the Software Package DUNE.- Direct Numerical Simulation of Jet in Crossflow Actuators.- Laminar Heat Transfer From the Stagnation Region of a Circular Cylinder at Re=140?000.- Conditional Statistics Along Gradient Trajectories in Fluid Turbulence.- Direct Numerical Simulation of Single Gaseous Bubbles in Viscous Liquids.- Wall Heat Load in Unsteady and Pulsating Combustor Flow.- Implicit LES ofPassive-Scalar Mixing in a Confined Rectangular-Jet Reactor.- Numerical Simulation of Riblet Controlled Spatial Transition.- Understanding the Dynamics and Control of a Turbulent Impinging Jet via Pulsation and Swirl Using Large Eddy Simulation.- Stability Analysis of a Coupled Helmholtz Resonator with Large Eddy Simulation.- Diffusers with Three-Dimensional Separation as Test Bed for Hybrid LES/RANS Methods.- Final Report on Project GGT0607: Lattice Boltzmann Direct Numerical Simulations of Grid-Generated Turbulence.- Application of FDEM on the Numerical Simulation of Journal Bearings with Turbulence and Inertia Effects.- Numerical Analysis of Transition Effects in 3D Hypersonic Intake Flows.- Preinvestigations of a Redesigned HIRENASD Wing Model in Preparation for New Aero-Structural Dynamic Experiments in ETW.- Transport and Climate.- Modelling Regional Climate Change in Southwest Germany.- Modelling Convection over West Africa.- Miscellaneous Topics.- Molecular Modeling of Hydrogen Bonding Fluids: Vapor-Liquid Coexistence and Interfacial Properties.- Towards a Dynamical Model of Mars’ Evolution.- Computational Considerations for Satellite-Based Geopotential Recovery.- Simulative Analysis of Vehicle-to-X Communication considering Traffic Safety and Efficiency.- Modelling Structural Failure with Finite Element Analysis of Controlled Demolition of Buildings by Explosives Using LS-DYNA.

Leseproben

"Numerical Models for Emission Line Nebulae in High Redshift Radio Galaxies (S. 3-4)

Summary. We examine models for line-emitting gas nebulae around powerful radio galaxies in the early universe. The models assume that either the emitting gas clouds are embedded in the shocked ambient gas and driven outwards with it or that they are created and sustained by multi-phase turbulence in the jet cocoon. For this, we perform jet simulations with realistic density contrasts on large scales and on typical activity time scales of several ten million years. The employed magnetohydrodynamics code NIRVANA has been optimized for the NEC SX machines in the previous years and now runs very e?ciently on the SX-6 and SX-8, allowing us simulations both in axisymmetry and full three dimensions. Future simulations on the SX-9 will bene?t signi?cantly from the increased number of shared memory processors per node for the axisymmetric runs, where an MPI-parallelization is generally ine?cient for our setup due to communication overhead.

1 Introduction

Extragalactic jets are amongst the most spectacular phenomena in astrophysics: These collimated beams of dilute but highly energetic plasma are formed in the environs of active black holes, on scales of milliparsecs3 with speeds very close to the speed of light, and propagate far outwards, eventually leaving the galaxy and pushing through the intergalactic gas at hundreds or even thousands of kiloparsecs.

Over these more than seven orders of magnitude in length, they remain collimated and deposit a large fraction of their huge kinetic energies of ~ 1039 watts on the ambient gas. Yet, due to their low densities relative to the gas in galaxy cluster, they expand only slowly and reach their largest sizes only after several tens of millions of years. While these objects have been discovered already more than 50 years ago as double radio sources, only improving observational techniques made it possible in the 1970s and 1980s to realize the underlying physical mechanism of supersonic beams carrying large amounts of kinetic energy.

Jets do not only occur in the local universe, but also at high redshifts [13], corresponding to a time only some billion years after the big bang, when galaxies were still actively forming. At redshifts z > 0.5, radio galaxies often show luminous emission regions extending far beyond the galaxy itself, which are aligned with the radio source (“alignment e?ect”). These gas nebulae consist of an outer quiescent component, usually outside the radio structures, and an inner component with strongly distorted kinematics and clumpy and irregular structure [15]."