Published in Sarov (Arzamas-16), Nizhegorodskaya oblast
NUCLEAR CENTER -
ALL-RUSSIAN RESEARCH INSTITUTE
OF EXPERIMENTAL PHYSICS
Русский | English
Issue No 1, 2003
A METHOD OF UNDETERMINED COEFFICIENTS FOR SOLVING RIEMANN PROBLEM
T.A. Kobzeva, N.Ya. MoiseevThe paper deals with an approach to Riemann problem solution based on the replacement of complex equations of state by binomial equations with undetermined coefficients. The coefficients are chosen to provide coincidence of problem solutions for binomial and original equations of state. With specific values of coefficients media are described by binomial equations of state for which Riemann problem is completely solved. The iterative process of problems solution for media described by binomial equations of state relies upon a method of inverse parabolic interpolation and has a cubic rate of convergence. For solving problems in an interactive mode a program has been designed in C++ in Visual C++ environment as SDI-application. The program has a suitable interface for initial data preparation and visualization of the results of Riemann problem computation.
VANT. Ser.: Mat. Mod. Fiz. Proc. 2003. No 1. P. 3-9.
|NUMERICAL MODELLING OF MAGNETIC SELF-INSULATION IN A COAXIAL VACUUM WAVE LINE
N.V. Egorov, A.V. Ivanovsky, E.A. Posdyaeva, A.A. Solov'evA technique for solving a problem on magnetic self-insulation of vacuum wave line in two dimensions, as well as its one-dimensional variant for a steady-state mode of magnetic self-insulation have been developed. Computational data, obtained with these techniques were compared. A design-theoretical study of magnetic self-insulation steady-state modes for vacuum wave line was made using one-dimensional technique.
VANT. Ser.: Mat. Mod. Fiz. Proc. 2003. No 1. P. 10-19.
|EGAK++ PROGRAM COMPLEX FOR MODELLING ON AN INBUILT ADAPTIVE REFINED MESH
Yu.V. Yanilkin, S.P. Belyaev, A.V. Gorodnichev, E.G. Voronov, A.R. Guzhova, L.I. Degtyarenko, G.V. Zharova, P.A. Kucherova, A.L. Stadnik, N.A. KhovrinThe paper describes EGAK++ program complex, based on EGAK Complex using a movable inbuilt adaptive refined mesh to single out the features of fluids in multicomponent continuum mechanics problems. The improvement of accuracy and efficiency in computations with EGAK++ complex is exemplified by several problems.
VANT. Ser.: Mat. Mod. Fiz. Proc. 2003. No 1. P. 20-28.
|A PIECEWISE-PARABOLIC METHOD USE FOR SOLVING ADVECTION EQUATION IN EGAK++ COMPLEX
P.A. Kucherova, Yu.V. Yanilkin, E.A. GoncharovThe paper proposes the 2D piecewise-parabolic method (PPM method) with a new algorithm of solution monotonization to enhance the order of approximating convective members of gas-dynamic equations at the second computation stage in Lagrangian Eulerian method of EGAK++ complex. PPM method is used for calculating density and energy flows. After estimation of mass and energy flows they are corrected so as to monotonize the solution in the case of maximum principle violation, as the above algorithm does not provide this principle implementation. A new algorithm for solution monotinization has been proposed. The paper presents comparative properties of donor and piecewise-parabolic methods with monotonization algorithm based on 1 D and 2 D test and methodical problems. The piecewise-parabolic method with solution monotonization algorithm was developed and implemented in EGAK++ complex for computing problems on both regular and refined meshes. The distinctions in formulas, appearing under calculation on the refined mesh are studied. The results of computations with PPM method on regular and refined meshes are given.
VANT. Ser.: Mat. Mod. Fiz. Proc. 2003. No 1. P. 29-35.
|EXACT SOLUTIONS IN RADIATION GAS DYNAMICS
A.A. ShestakovIt is the author's opinion that exact solutions for radiation gas-dynamic system taking into account radiation pulse in medium motion equations were first constructed in the paper. The solutions are constructed for a combined system of gas-dynamic and radiation transfer equations in different approximations with specially fitted coefficients of absorption, scattering, source and internal energy of material.
VANT. Ser.: Mat. Mod. Fiz. Proc. 2003. No 1. P. 36-50.
|A STUDY OF FAST CHARGED PARTICLE TRANSFER EFFECT ON THERMONUCLEAR TARGETS COMBUSTION
S.A. Belkov, G.V. Dolgoleva, V.F. ErmolovichFor adequate description of laser plasma physics a great number of physical processes must be taken into account. Energy, pulse and mass transfer by fast charged particles, produced by thermonuclear and neutron-nuclear reactions, is one of such processes. Generation and transfer of charged particles resulting from thermonuclear reactions in burning deuterium-tritium plasma are very essential. The model is to reflect where and how charged particles put out their energy, that is to calculate time-dependent energy, pulse and mass transfer by fast charged participles. Two models describing this process: kinetic and diffusion are studied. The paper presents a mathematical setting of original problem and results of numerical study of fast charged particles transfer effect on compression and combustion of the capsule, designed in Los Alamos and proposed in the NIF Laser Project (US).
VANT. Ser.: Mat. Mod. Fiz. Proc. 2003. No 1. P. 51-55.
|A STUDY OF THE EFFECT OF VARIOUS TURBULENT MIXING MODELS IN THE TARGET COMPRESSION CALCULATIONS FOR NIF FACILITY WITHIN SND TECHNIQUE
G.V. Dolgoleva, E.A. Novikova, V.P. StatsenkoIn the target compression calculations the processes of turbulent mixing are studied. The numerical SND technique includes two models of turbulent mixing (gradient and -models), allowing quantitative study of mixing zone development and describing satisfactorily fluids with wide range of parameters. The results of comparative calculations of a target with these models are presented. The target proposed for use at the NIF facility (US) has been chosen for study. The calculations of turbulent mixing showed on the whole satisfactory agreement of turbulent quantities for both minimal and maximal values of changeable parameters in the above models.
VANT. Ser.: Mat. Mod. Fiz. Proc. 2003. No 1. P. 56-60.
|SYSTEM PROTOTYPE OF APPLICATION DEVELOPMENT AND AUTOMATIC PROGRAM PARALLELIZATION FOR HETEROGENEOUS MULTIPROGRAM SYSTEMS
A.N. Sal'nikov, A.N. Sazonov, M.V. KarevAlgorithm graph is automatically constructed according to a serial program code in C. Using algorithm graph as the base a parallel program is constructed to be executed on multiprocessor system with algorithm graph nodes selected for executing on the processor dynamically. The proposed tool for parallel programming support is to take up some functions of operational system and take care singly to execute parallel program on a specific multiprocessor system with regard to its architectural characteristics and an informational problem structure. For balancing processor and communication channel load a problem on scheduling the multiprocessor system work on an algorithm graph has been solved.
VANT. Ser.: Mat. Mod. Fiz. Proc. 2003. No 1. P. 61-68.
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