ISSUES OF ATOMIC SCIENCE AND TECHNOLOGY
Series: Mathematical simulation of physical processes

Year 2011 2010 2009
Issue 1-2-3-4 1-2-3-4 1-2-3-4

2011
ISSUE 3

ABSTRACTS:

UDK 681.324
MOLECULAR DYNAMICS DIFFERENCE SCHEMES. 2. 2D TESTS SYSTEM / V. Å. Shemarulin, V. N. Sofronov, Ê. S. Mokina // P. 3–15.
Described here is tests system set by authors to verify codes developed for molecular dynamics problems. The given tests system is intended to verify the resistance, accuracy and conservative properties of difference schemes, and is given as an accurate solution list for Newton , Morse potentials, modified Morse potential and Laennard-Jones potentials. Key tests are based on Euler and Lagrange potential for Newton potential. Exact solutions of a number of one-dimensional problems are given along with two-dimensional solutions.
Dynamic stability problem of three bodies is considered. At present, this problem remains open in general formulation.
Keywords: molecular dynamics, Newton potential, classical and modified Morse potentials, Lennard-Jones potential, many-body problem, analytical solution of 2D problems of material point motion systems, Euler collinear solutions, triangular Lagrangian solutions, libration points and the problem of their stability, Routh condition.

UDK 519.6
NUMERICAL SIMULATION OF EXPLOSIVE COMBUSTION AND DETONATION USING EULERIAN GAS-DYNAMIC COMPUTATIONS / Yu. V. Yanilkin, I. I. Karpenko, Å. S. Gavrilova, L. I. Degtyarenko, Å. À. Mavrina, Î. Î. Toporova // P. 16–28.
Described here are explosive combustion and detonation methods implemented in EGAK and TREK codes using fixed grids. Computational results of 2D problems using fixed grids are also given with detonation control programs, two-component model of Tarver kinetics and four-component model of Morozov-Karpenko kinetics. Computations were carried out with adaptive non-integral grid.
Keywords: explosive, detonation, detonation velocity control, initiation time, Huygens principle, adaptive non-integral grid, Tarver kinetics, Morozov-Karpenko kinetics.

UDK 519.6:536.71
SOLUTION OF RADIATION TRANSFER KINETIC EQUATION USING AVERAGED COSINE METHOD / À. S. Egorova, N. G. Karlykhanov // P. 29–38.
Suggested here is the method of radiation transfer kinetic equation solution based on initial equation averaging over angle variable. As opposed to quasi-diffusion method, one-step equation with photon direction averaged cosine closure was set up. Difference schemes were constructed in terms of TVD approaches. The limiters of min mod and Chakravati-Osher types were used taken from n-th times step (linear TVD scheme), as well as from (n + 1)-th step (non-linear TVD scheme). The obtained system of nonlinear algebraic equations was solved with Newton method. The applicability of the method suggested, was tested using solution of a number of method problems.
Keywords: radiation transfer, TVD approach, transfer one-step equations with averaged cosines.

UDK 539.4
ENERGY MODEL OF METAL HARDENING / Î. N. Ignatova, V. À. Raevskiy // P. 39–44.
Energy model of shear strength accounting for the value and rate of plastic deformation, as well as softening connected with temperature annealing and dislocation annihilation, is suggested on Baily hypothesis for connection between strain hardening and strain energy of defects. It is assumed that accumulation of strain energy of defects is determined by plastic work of deformation. The suggested model adequately agrees with experimental data available for copper up to P = 70 GPa, for aluminum up to P = 10 GPa, for tantalum up to P = 20 GPa.
Keywords: strength, model, hardening, deformation, shockwave.

UDK 624.131.43, 624.131.522
ON CERTAIN PECULIARITIES OF MODELS OF MULTIPHASE SOILS MECHANICS / N. Å. Galiullina, Ì. G. Khramchenkov, E. Ì. Khramchenkov, À. N. Chekalin, V. V. Mikhailov // P. 45–51.
Considered here is consolidation equation of soil under load (Florin equation) for the case of immiscible liquid saturation of soil, as well as for the case of liquid phase sub-saturation of soil. Deformation detected effects important for interpretation of experimental results of compression tests for unsaturated and multiphase soils, were analyzed. The suggested models allow computation of the effect of such factors as operating time of water beds at late stage, layer discharge of storage-preserved matters, isolating layer penetration of contaminations.
Keywords: hydrodynamics, mass balance equation, deformations, effective stresses.
     
UDK 519.6
MODIFICATION OF BOWER-WATSON ALGORITHM OF TOPOLOGICALLY 2D UNSTRUCTURED GRIDS GENERATION IN THE RANGES OF ARBITRARY FORMS / Ì. L. Sidorov // P. 52–62.
Suggested here is Bower-Watson algorithm modification of topologically 2D triangular unstructured grid generation in the ranges of arbitrary form and connection. The algorithm consists of four parts: 1) triangulation of the reference profile; 2) minimization of geometrical measure of non-regularity; 3) minimization of topological measure of non-regularity; 4) refinement of the grid obtained (optional).
Keywords: unstructured (irregular) grid, triangulation, Bower-Watson method, topological optimization, geometrical optimization.

UDK 519.6
IMPLEMENTAION FEATURES OF COMMUNICATION SOFTWARE OF COMPACT SUPERCOMPUTERS WHEN USING SWITCHLESS TECHNOLOGIES / D. À. Zhukov, V. Ì. Vyalukhin // P. 63–67.
Described here are implementation features of communication software for compact high-performance computer systems with application of InfiniBand-based switchless technologies. Communication software settings, as well as MPI interprocessor communication algorithms in switchless communication environment are described. These software solutions are considered as applied to compact high-performance computer system developed in RFNC-VNIIEF.
Keywords: switchless technologies, communication software, interprocessor exchange system, InfiniBand architecture, MPI-processor, compact supercomputer.

UDK 519.6
UNIFIED COMMUNICATION ENVIRONMENT CONTROL USING PROGRAM-INDEPENDENT COMMUNICATION SUB-SYSTEMS / V. G. Basalov // P. 68–74.
Described here is the software package Multi Cluster Subnet Manager, developed to manage program-independent communication sub-systems as a part of the unified communication system. Mechanisms implemented in this package to detect, configure, activate and support program-independent communication sub-systems are described.
Keywords: multiprocessor, unified communication environment, program-independent communication sub-system, logical clusterization, subnet manager.

Reference date about the authors

Year 2011 2010 2009
Issue 1-2-3-4 1-2-3-4 1-2-3-4