High Performance Computing in Science and Engineering '09 Transactions of the High Performance Computing Center, Stuttgart (HLRS) 2009
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Wolfgang E. Nagel, Dietmar B. Kröner, Michael Resch
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Wolfgang E. Nagel
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High Performance Computing in Science and Engineering '09 Transactions of the High Performance Computing Center, Stuttgart (HLRS) 2009
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Springer-Verlag
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9783642046650
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1
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CHF 151.60
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Wahrscheinlichkeitstheorie, Stochastik, Mathematische Statistik
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English
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551
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Wasserzeichen/DRM
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PC/MAC/eReader/Tablet
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PDF
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.
"
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]."
Preface
5
Contents
8
Physics
12
Numerical Models for Emission Line Nebulae in High Redshift Radio Galaxies
13
Introduction
13
Numerical Method
15
Computational and Scientific Results
15
Performance
15
High Redshift Radio Galaxies
15
Summary
24
References
25
The SuperN-Project: Current Advances in Understanding Core Collapse Supernovae
26
Introduction
26
Numerical Models
27
History and Constraints
27
Recent Calculations and the Need for TFlop Simulations
29
The Mathematical Model
30
``Ray-by-Ray Plus'' Variable Eddington Factor Solution of the Neutrino Transport Problem
30
Parallelization
34
Recent Results and Ongoing Work
35
Long-time Simulations of Massive Progenitor Models
35
Explosion Models of Oxygen-neon-magnesium Cores
36
Conclusions and Outlook
38
References
39
Using Computational Steering to Explore the Parameter Space of Stability in a Suspension
42
Introduction
42
Simulation Method
43
Simulation Steering
47
Results
48
Pressure Filtration
48
Observation of Cluster Formation
49
Sedimentation: Hydrodynamic Interaction
52
Summary
53
References
53
Solid State Physics
58
Adsorption of Cysteine on the Au(110)-surface: A Density Functional Theory Study
61
Introduction
61
Computational Methods
62
Results and Discussion
63
Au(110) Surface Energy
63
Au (110)-(1 x 2) Vacancy Formation Energy
64
Cysteine Dimers: The Carboxyl-Carboxyl Hydrogen Bond
66
Outlook
67
References
67
Ab-initio Characterization of Colloidal IV-VI Semiconductor Quantum Dots
69
Introduction
69
Computational Method
70
Theoretical Background
70
Computational Cost
71
Nanocrystal Construction Using Supercel
