Issue No 3, 1991
NUMERICAL SIMULATION OF SPATIAL FLOW OVER A CYLINDER WITH A DISC NOZZLE AT THE FRONT END
O.M. Veliсhкo, A.N. Razin
VANT. Ser. Mat. Mod. Fiz. Proc. 1991. No 3. P. 3-6.
Spatial flow over a cylinder with a disc nozzle at the front end is considered for μ∞= 3 and attack angle α = 5º. The simulation is carried out within an inviscid nonconducting gas model. Three-dimensional time- dependent Euler equations are integrated with Godunov difference method. A time-independent flow-pattem is obtained by stabilizing over time within the time-dependent process. A complex flow structure occurring between the body and head shock surfaces is illustrated graphically. Aerodynamic configuration characteristics are derived from pressure distribution obtained. It should be noted that for a spatial flow over the configuration the longitudinal force coefficient is twice the wave impedance coefficient for axisymmetric flow. The problem is numerically solved with a multiprocessor-oriented program written in FORTRAN-77. Gas dynamic parameters are calculated in parallel mode which allows to substantially reduce the computation time.
|DETONATION BURNING OF A CYLINDER DT TARGET FOR HEAVY-ION FUSION
E.A. Zabrodina, Ya.M. Kazhdan, M.D. Churazоv
VANT. Ser. Mat. Mod. Fiz. Proc. 1991. No 3. P. 7-11.
Calculations of thermonuclear cylinder DT target burning are examined. Methods are developed and results are presented for two-dimensional model including four fusion reaction. The effect of introducing 3Не into D fuel is outlined.
|EXACT SOLUTIONS FOR A SYSTEM OF ENERGY AMD RADIATION TRANSPORT EQUATIONS WITH ANISOTROPIC SCATTERING IN A MULTIDIMENSIONAL CASE
VANT. Ser. Mat. Mod. Fiz. Proc. 1991. No 3. P. 12-14.
Some exact solutions are examined for a system of energy and radiation transport equations with anisotropic scattering in a multidimensional case.
The solutions obtained can bе used to make difference methods more perfect.
|ON VARIATIONAL FINITE-DIFFERENCE SCHEME STABILITY OF THE PARTICLE METHOD FOR VLASOV EQUATIONS IN SELF-CONSISTENT ELECTROSTATIC APPROXIMATION. PT. 1. SUFFICIENT CONDITIONS FOR ACTUAL STABILITY
VANT. Ser. Mat. Mod. Fiz. Proc. 1991. No 3. P. 15-23.
Stability of small particle coordinate perturbations is investigated in variational leap-frog-type difference schemes for collisionless plasma in a self-consistent electric field. Difference schemes involving arbitrary macroparticle structures having an arbitrary number of degrees of freedom and basic functions for describing electric field potential are examined. Sufficient conditions are obtained for actual stability of such schemes that is those sufficient for stability of ρ harmonics having physical instability (their growth is not prevented by decreasing the timestep size in a difference scheme) and also for ordinary stability over initial data for others.
|ON VARIATIONAL FINITE-DIFFERENCE SCHEME STABILITY OF THE PARTICLE METHOD FOR VLASOV EQUATIONS IN SELF-CONSISTENT ELECTROSTATIC APPROXIMATION. PT. 2. UNREMOVABLE INSTABILITY. EXAMPLES
VANT. Ser. Mat. Mod. Fiz. Proc. 1991. No 3. P. 24-30.
Stability of small particle coordinate perturbations in difference schemes of the particle leap-frog-type method is investigated for collisionlfcjs plasma in a self-consistent electric field for the case of arbitrary macroparticle structure having an arbitrary number of degrees of freedom and arbitrary basic functions for describing electric field potential. For difference schemes, instability presence is proved which is not removable by decreasing the timestep size and its correspondence with that of small plasma particle coordinate perturbations is established for differential equations of particle motion. Bo.th upper and lower estimates were obtained for maximum growth increments of unstable perturbations in difference schemes under consideration which are then checked for a one-dimensional case.
For a one-dimensional case, sufficient stability conditions obtained in the first part are shown to give a finite (nonzero) acceptable timestep value inversely proportional to plasma frequency as the grid for the potential becomes finer and the number of particles decreasing in size grows simultaneously.
|THREE-DIMENSIONAL GRID DESIGN TECHNOLOGIES FOR PROBLEMS IN GAS AERODYNAMICS
VANT. Ser. Mat. Mod. Fiz. Proc. 1991. No 3. P. 31-45.
A classification of difference grids used for solving three-demensio-nal problems is given. Grid design phases, methods, numerical algorithms and programs are described together with their application to spatial problems in gas aerodynamics. The bibliography is presented.
|STABILITY АND MONOTONICITY OF TIME-DEPENDENT HEAT CONDUCTION PROBLEM SOLUTIONS OBTAINED WITH FINITE-ELEMENT AND FINITE-DIFFERENCE METHODS
A.G. Tsitsin, K.E. Afanasiev
VANT. Ser. Mat. Mod. Fiz. Proc. 1991. No 3. P. 46-49.
Increasing finite element and finite-difference scheme accuracy order results in additional restrictions on dimension- less timestep size (similar to Courant criterion) which are due to the solution monotonicity over space. For a one-dimensional heat conduction problem with linear Laplace operator approximation, a range of allowed Courant criterion values ensuring the stability and monotonicity of schemes under question is plotted.
|RUN-TIME SYSTEM FOR LANGUAGE DESIGN AND COMPILER CONSTRUCTION (AVTRAN)
M.I. Kaplunоv, V.I. Filatоv
VANT. Ser. Mat. Mod. Fiz. Proc. 1991. No 3. P. 50-54.
AVTRAN system is intended to automate afforts involved in special-purpose language and compiler developments. This allows to reduce the design of a syntax-oriented compiler to normal BNF language grammar description and semantic procedure definitions.
|DISPLAY CONNECTION UNIT
S.V. Gamоlуa, E.V. Gladilin, Yu.I. Kоnоtоp
VANT. Ser. Mat. Mod. Fiz. Proc. 1991. No 3. P. 55-60.
One of the ways is considered for developing group control units using a display connection unit as an example. Display Connection Unit structure and performance data are given; advantages and further design trends of such class units are described in terms of developing LANs for remote data processing within a great computer center. Estimates are obtained of response time achieved by the generic UST-1 version for the KDE-810A display performing with the ES EVM computers. Operational recommendations are presented for KDE-810A connected to the UST-1 unit.
|INTEDA DATABASE SYSTEM FOR COMPUTATIONAL PHYSICS PROGRAM PACKAGES (SVM ES IMPLEMENTATION)
L.N. Aleksandrova, I.D. Bокоva, V.V. Kоmоsко, I.А. Коmоsко, E.V. Marкоva, M.A. Safonоva, H.V. Pilippоv
VANT. Ser. Mat. Mod. Fiz. Proc. 1991. No 3. P. 61-66.
The INTEDA database system comprises a database set, meta-database set, meta-data operation facilities based on data dictionary system, and special-purpose database management system, ODDA. The paper focusses on two last components, their inplementation and functioning in the SVM ES environment.
The database set and appropriate meta-database set form a universe and satisfy SOYUZ package requirement in every state of computation process.
Meta-database operation facilities axe two non-intersecting subsets; general-purpose facilities of the data dictionary system, RIS-SLOVAR, performing within the OS ES, and special-purpose facilities of the INTEDA database system which perform in SVM ES.
ODDA is a special management system for large hierarchical databases. Data are manipulated on the entity level in the universe. The access mechanism of an application does not depend on hardware and software environment.
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