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Since 1978
Published in Sarov (Arzamas-16), Nizhegorodskaya oblast |
RUSSIAN FEDERAL
NUCLEAR CENTER -
ALL-RUSSIAN RESEARCH INSTITUTE
OF EXPERIMENTAL PHYSICS |
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 Русский |  English
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Issue No 4, 2009 |
SOLVING HEAT TRANSFER EQUATIONS ON UNSTRUCTURED DIRICHLET GRIDS USING AN EFFICIENT SCHEME
I. D. Sofronov, A. I. Panov, A. V. Samodolov
VANT. Ser.: Mat. Mod. Fiz. Proc. 2009. No 4. P. 3-11.
An efficient difference scheme for solving multidimensional heat transfer equations on unstructured Dirichlet grids is described. The scheme was proposed and substantiated by I. D. Sofronov. A specific feature of this scheme is that it can be used on highly heterogeneous grids of cells with a variable number of vertices. The scheme can be used to solve both linear and quasi-linear heat transfer equations in 2D and 3D cases.
Key words: unstructured Dirichlet grids, direction splitting scheme, numerical solution of two-dimensional and three-dimensional heat transfer problems.
| | CODE SOLYARIS FOR NUMERICAL SIMULATION OF RADIATION TRANSPORT IN MULTIDIMENSIONAL STRUCTURES WITH VACUUM SPACES WITH REGARD TO GAS DYNAMIC MOTION AND OTHER PHYSICAL PROCESSES ON MULTIPROCESSORS O. A. Abramova,  , G. V. Dolgoleva, T. V. Korol’kova, S. N. Krupina, V. M. Mel’nikov, V. F. Mironova, E. A. Novikova, P. I. Pevnaya, E. I. Ryabov, I. N. Salova, B. P. Tikhomirov, Yu. A. Tsibereva, R. M. Shagaliev, B. N. Shamraev
VANT. Ser.: Mat. Mod. Fiz. Proc. 2009. No 4. P. 12-21.
The paper describes code SOLYARIS for ID numerical simulation on multiprocessor of the radiation transport in complex-geometry multidimensional structures with optically dense and optically transparent regions with regard to gas dynamic motion and spectral radiation transport in a material in quasi-diffusion approximation. The paper presents physico-mathematical models and describes the main ideas of the technique allowing simulation of physical processes of various kinds, as well as the main algorithms implemented and approaches to parallelization, and also gives results of efficient parallelization.
Key words: numerical simulation, spectral radiation transport in vacuum, heat conduction, quasi-diffusion approximation, one-dimensional approximation, gas dynamics, spectral diffusion, non-equilibrium diffusion, view factors, fusion burning kinetics, laser energy absorption and transport, HE decomposition and burning kinetics, upheaval of polymer coating, melting, parallel computations.
| | GENERALIZED DIFFERENTIAL RELATIONS ON A SHOCK A. L. Adrianov
VANT. Ser.: Mat. Mod. Fiz. Proc. 2009. No 4. P. 22-30.
The paper describes the derivation of generalized differential relations on a curvilinear shock in non-uniform flow of a viscous heat-conductive ideal gas. “Viscous” terms have been taken into account with approximation to a shear layer of asymptotical order O(1). The system of symbolic transformations on a computer was used during the relation derivation process. Ultimately, the derived relations are written in the matrix form with a small parameter in the highest derivatives and nonlinear terms. Coefficients are not given for these relations because of their awkwardness. In a limit non-viscous case, the generalized differential relations identically coincide with the known results.
Key words: curvilinear shock, viscous heat-conductive ideal gas, shear layer, schematic shock representation by strong gas-dynamic discontinuity, system of analytic symbolic transformations on computer, generalized differential relations (conditions) on curvilinear shock, asymptotic approach, small parameter, limiting non-viscous case, boundary effect, additional differential constraint, eddy interaction model, analytical solution.
| | CODE SNDMA FOR CALCULATION OF EMITTING NON-EQUI-LIBRIUM MOLECULAR PLASMA FLOWS V. D. Atamanenko, G. V. Dolgoleva, V. A. Zhmailo, L V. Popov
VANT. Ser.: Mat. Mod. Fiz. Proc. 2009. No 4. P. 31-44.
The paper presents ..SNDMA code for the calculation of flows of emitting non-equilibrium molecular plasma jointly with the kinetics of chemical, photo-chemical, plasma-chemical, photo- and radiation-plasma-chemical reactions in air plasma. The physical model and numerical solution techniques are described and the calculated results are compared with the analytical solutions to test problems.
Key words: calculation of flows of emitting non-equilibrium molecular plasma, numerical solution technique.
| | SOLUTION OF THE HEAT CONDUCTION PROBLEM FOR A CYLINDER OF FINITE DIMENSIONS WITH INTERNAL HEAT SOURCES M. V. Kashcheev
VANT. Ser.: Mat. Mod. Fiz. Proc. 2009. No 4. P. 45-48.
The paper considers the problem of a cooling-down homogeneous cylindrical rod of a round cross-section and finite length located in the environment, which temperature varies with time. The heat exchange according to the Newton law is observed on the rod’s boundaries. The time-dependent heat conduction problem in a finite-size cylinder has been solved using the method of finite integral transformations.
Key words: heat conduction problem, cylindrical rod, interior heat sources, method of finite integral transformations, differential operator, characteristic equation, transformation kernel, boundary, surrounding medium.
| | TIME INSTABILITY MEASUREMENT TOOLS FOR MULTIPROCESSORS Yu. G. Bartenev, A. M. Vargin, V. A. Erzunov, V. V. Koshelev, D. V. Kulnev, D. I. Lipov, P. S. Lobanov, A. V. Lomtev, D. A. Novaev, A. N. Petrik, T. V. Semenova, G. P. Semenov,  , E. B. Shchanikova
VANT. Ser.: Mat. Mod. Fiz. Proc. 2009. No 4. P. 49-59.
The paper describes Noise Measurement Suite, which is a software package for measurements of noises in a parallel computer with a large number of processors impacting the job parallelization efficiency. In literature, noise means random interferences during the process of computations, for example, owing to conflicts in a set of operating components, or asynchronous operations of the parallel computer’s control system on various processors. The suite of tools allows estimating the impact of noises on the performance of parallel user applications on the given computer and assessing a possibility of scaling the given firmware platform to create a more powerful computer system with the required performance of the given parallel applications.
Key words: multiprocessor computers, parallel application, process, operating system, Python programming language.
| | JOB BATCH PROCESSING SYSTEM JAM A. B. Kiselev, S. N. Kiselev
VANT. Ser.: Mat. Mod. Fiz. Proc. 2009. No 4. P. 60-66.
The job batch processing system JAM (system software JAM) described in the paper has been created to provide effective use of computing resources of the cluster with JAM. For this purpose, the algorithm of filling gaps (backfill algorithm), combinations of this algorithm with the worst-fit and best-fit algorithms and algorithms of allocating jobs to the cluster nodes with regard to the structure of interconnects of its high-performance communication network have been implemented. The paper gives the general description of the system and the scheme of interconnections of its program components, in particular, interconnections between scheduler and node demons of JAM implemented owing to the use of JINI technology and JavaSpace service. The system capabilities, which are absent in similar commercial software products, or products for free release, are described, namely:
- data transfer from output flow and job process diagnostics flow to the program server located on the control development computer;
- interaction between the server and executable components implemented using JINI technology with JavaSpace service;
- job allocation to the adjacent nodes connected to the adjacent switches of the high-performance communication network;
- adjustable mechanism of the job “pulse” monitoring that allows automatically finishing a hung-up job. The job batch processing system JAM has been integrated with a united queue system (UQS) and in this combination it can be used for management of a heterogeneous computer complex at large Computation Center.
Key words: multiprocessor computing system, job batch processing, job batch planning, backfill.
| | THE ENVIRONMENT FOR INTERACTIVELY VIEWING SIMULATIONS ON SUPERCOMPUTERS P. A. Vasyov
VANT. Ser.: Mat. Mod. Fiz. Proc. 2009. No 4. P. 67-77.
An ability to interact with a running application may be very useful for the user to debug his parallel applications and reduce the numerical experiment duration. Such interaction implies monitoring of the parallel application state and a possibility to control its operation. However, standard technologies allowing such scenario implementation are not available at present time. So, it is of great interest to improve the modern computing systems in order to equip them with the function of interactively starting jobs. Another useful feature of interactive mode is that it allows viewing remote data, i.e. viewing data not transmitted to the given user’s computer. This makes it possible to reduce the waiting period between the completed computations and the result viewing start time and also save the network and disk resources. The paper presents simple and easy to use software system implementing the above-mentioned interactive scenarios. The system is intended for monitoring and control of small- and middle-size jobs, allows viewing remote data using modern technologies for construction of the user interface and can be used both in local and global networks.
Key words: visualization, parallel computations, interface.
| | THE EFFECT OF “REPACKING” THE RADIATION BEAM PROJECTIONS FROM RADIAL TO PARALLEL GEOMETRY ON THE QUALITY OF TOMOGRAPHIC IMAGES S. A. Lavrov, E. N. Simonov
VANT. Ser.: Mat. Mod. Fiz. Proc. 2009. No 4. P. 78-84.
The paper considers the algorithms of reconstructing images using the inverse projecting method with filtering by folding for the radial and parallel scanning geometries. The algorithm of repacking the radiation beam projections from radial to parallel geometries is presented. The paper shows that the difference of images between the radial geometry and the parallel geometry after repacking has been performed becomes smaller (both for high-contrast and low-contrast objects) with the increased number of view angles.
Key words: X-ray computer tomography, radial and parallel scanning geometry, image reconstruction, repacking.
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