Published in Sarov (Arzamas-16), Nizhegorodskaya oblast
NUCLEAR CENTER -
ALL-RUSSIAN RESEARCH INSTITUTE
OF EXPERIMENTAL PHYSICS
Русский | English
Issue No 1, 2005
COMBINED ALGORITHM OF PARALLELIZING SOLUTION OF 2-D TRANSFER EQUATION ON NONORTHOGONAL SPATIAL GRIDS
R. M. Shagaliev, I. M. Belyakov, V. A. Shumilin, A. V. Alekseev, O. V. Butneva, A. Yu. Kostenko, A. A. Nuzhdin, N. P. Pleteneva, V. Yu. Rezchikov, S. V. SubbotThe paper deals with the creation of a combined algorithm for parallelizing numerical solution of 2-D equation of photon transfer with consideration of radiation interaction with medium. The equations are written in a cylinder coordinate system, structured nonorthogonal grids are used for spatial grids. The combined algorithm presupposes parallelizing numerical solution of transfer equation in spatial variables and in an energy one. The description of a parallel method and the results of numerical studies of efficiency on model problems are presented.
VANT. Ser.: Mat. Mod. Fiz. Proc. 2005. No 1. P. 3-8.
|REALIZATION OF THE FRONTAL ALGORITHM OF IRREGULAR QUADRANGULAR NETS BUILDING
A. V. ScovpenA two-dimensional algorithm and an irregular quadrangular nets building code were developed. The algorithm is made on the basis of Q-Morth algorithm suggested by C. Owen and relates to the indirect frontal methods of irregular quadrangular nets building. A preliminary region triangulation and the following triangle transformation with quadrangular cells formation were applied when building a net. Coordinates of boundary nodes represent input data. The algorithm works in the automatic mode and doesn’t modify boundary nodes. The derivable net is fully quadrangular if the region boundary consists of even number of edges. When the number of edges is odd a triangular cell appears in the net. The program established on the basis of the algorithm can be used as an independent net module in the computational modeling.
VANT. Ser.: Mat. Mod. Fiz. Proc. 2005. No 1. P. 9-30.
|SOLUTION TECHNIQUE FOR 2-D TRANSFER EQUATION ON NONREGULAR MULTIANGULAR GRIDS
A. N. Moskvin, V. A. ShumilinA conservative finite-difference scheme is built on multiangular spatial grids for solving 2-D transfer equation. A difference scheme is built in two steps. In the first step intermediate values of an unknown function in a calculational cell are found by an approximate solution of the equation of transfer along characteristics. In the second step a correction multiplier is found in a cell from a balance equation and all obtained values of an unknown function are multiplied by this multiplier. Economic algorithms implementing a method of point-to-point computations on spatial grids with arbitrary polygons as elements are developed. The technique efficiency is illustrated by numerical calculations.
VANT. Ser.: Mat. Mod. Fiz. Proc. 2005. No 1. P. 31-40.
|EXPERIMENTAL INVESTIGATION AND NUMERICAL STUDY OF DETONATION PROCESS DEVELOPMENT FOR EXPLOSIVES OF TATB TYPE
S. M. Bakhrakh, N. A. Volodina, M. O. Zaytseva, I. I. Karpenko, A. D. Kovtun, V. A. Komrachkov, Yu. M. Makarov, V. G. Morozov, L. A. RyabchunAn experimental investigation and a numerical simulation of detonation excitation of TATB explosives were undertaken. The experimental investigation was carried out for a detonation excitation at an interaction of shocks with different intensity as well as for the effects of desensitizing (explosive sensitivity decrease) and sensitizing (explosive sensitivity increase). A numerical simulation of experiments was performed on LEGAK complex using kinetics of explosion decomposition, proposed by Morozov group and implemented in Lagrangian setting in DMK, MIMOZA and D-methods. Kinetics model was generalized to non Lagrangian calculational grid. Calculational results and their comparison with experimental data are presented. The experimental and calculational data agree with each other. The whole set of experiments has been described with fixed kinetic and calculation parameters.
VANT. Ser.: Mat. Mod. Fiz. Proc. 2005. No 1. P. 41-56.
|COMPARISON OF SOME MODELS FOR COMPUTING THERMODYNAMIC PARAMETERS OF HETEROGENEOUS LAGRANGIAN CELLS
The paper gives a description of four models for computing mixed cells in D complex which can be used to solve numerically nonsta- tionary gas-dynamic problems in Lagrangian variables. A method of substance interface detection in mixed cells is described. The results of comparative calculations axe reported for different models.
VANT. Ser.: Mat. Mod. Fiz. Proc. 2005. No 1. P. 57-70.
|VISUALIZATION OF STREAM LINES AND METHODS FOR COMPLEX VISUALIZATION OF DESCRETE VECTOR FIELDS
K. V. Dedkova, D. V. Mogilenskikh, I. V. Pavlov, V. V. FedorovThe paper describes methods for post-processing and visualization of continuum mechanics problems numerically simulated with difference methods, in particular, processing and visualization of vector fields. Simulation methods using 2D regular difference grids are used as an example. A vector variable U is set for such a grid. Two coordinate components of the vector (Ux,Uy) are specified for each node. Each component is a scalar. Vector field is stored as two matrices Ux[M, N], Uy[M,N], where M, N are grid dimensionality. Paper describes: 1. Algorithm for approximate determination and visualization of stream lines (SL) — post-processing of the results and determination of implicit information. 2. Functions of SL visualization — visualization methods. 3. Methods of combined application of SL visualization with other visualization functions — information content increase. Ideas of Gouraund and Phong shading algorithms are proposed for determination of SL vector field. The paper presents methods of animating pseudo-dynamics of SL vector fields and their implementation.
VANT. Ser.: Mat. Mod. Fiz. Proc. 2005. No 1. P. 71-79.
|ALGORITHM CONTOUR FOR FINDING AND VISUALIZATION OF FLAT SECTIONS OF 3D-OBJECTS
S. V. Kolomeyko, S. N. Melnikova, D. V. MogilenskikhCombinatorial geometry is applied in Monte-Carlo methods for 3D-objects definition that allows prompt logical localization of particles. The evident advantage of the method lies in the relative shortness of complex geometry description. However, certain difficulties in geometry visual control exist because in this case visualization is more difficult than in the case of grid models. The paper discusses a solution (algorithm CONTOUR) for defining and visualization of arbitrary plane sections on the basis of procedures present in any code using Monte-Carlo method. It should be noted that the most evident method of visualization is section plane dense routing (rendering). The method has several shortcomings. The contour algorithm does not change the rule of rendering but interprets and processes rendering results in another way. The basis idea consists in considering the section plane as a discrete grid domain.
VANT. Ser.: Mat. Mod. Fiz. Proc. 2005. No 1. P. 80-91.
|RECENT TECHNOLOGY OF DESIGNING SIMULATOR FOR A CORE IN A RESEARCH REACTOR FOR EXPEDITIOUS SUPPORT AND OPERATION
Yu. E. Vaneev, N. Yu. MarikhinGeneral requirements are formulated for a program complex based on a parallelized version of the sensitive program MCU-RR/P and intending for computational support of research reactor operation with a core as the main component. The main technological regulations for developing such a simulator and the results of their implementation as applied to the reactor SM are presented.
VANT. Ser.: Mat. Mod. Fiz. Proc. 2005. No 1. P. 92-99.
|SERVICE APPLICATION FOR STORAGE AND PROCESSING OF THE RESULTS OF MATHEMATICAL PHYSICS PROBLEMS SIMULATED WITH THE SOFTWARE COMPLEXES
S. V. Gagarin, L. M. Zueva, V. V. Komosko, S. A. Markelenkov, S. V. Morozov, P. A. Novgorodtseva, N. N. Sokolova, A. V. StepanovThe paper describes SOVT service application used to accumulate, process and present results obtained in the numerical simulation of mathematical physics problems. SOVT incorporates a number of independent modules interacting through a database of standard time tables (STTBD) managed by Oracle. The modules interact with STTBD independently (converters), or as components of code packages (libraries of STTBD access procedures), or as components of specialized data processing and presentation systems (STTBD access server). SOVT selects from STTBD information on several functions of different problems calculated by different codes, provides their preliminary processing, and forwards them for further processing and analysis made with the standard data processing and presentation systems (Matlab, Excel) or with a specialized data visualization system VIZI1D, developed in RFNC-VNIITF.
VANT. Ser.: Mat. Mod. Fiz. Proc. 2005. No 1. P. 100-110.
|SERVICE APPLICATION FOR MULTITASKING ANALYSIS OF THE RESULTS OBTAINED IN THE NUMERICAL SIMULATION OF MATHEMATICAL PHYSICS PROBLEMS
S. V. Gagarin, K. V. Dedkova, V. V. Komosko, V. V. Fedorov, S. V. MorozovA service application for analyzing the results of problems simulated by different software complexes and stored in the database of standard time tables is described. With this application results a great number of problems is analyzed with the same promptness regardless of when they were obtained and whether they were obtained by one or more codes. The application Is based on the STTBD access server and VIZI-ID, Matlab and MS Excel data processing and visualization systems. It is written in C++ for Microsoft Visual Studio with use of COM technology and Oracle database management system.
VANT. Ser.: Mat. Mod. Fiz. Proc. 2005. No 1. P. 111-116.
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