THE MAIN CONCEPTS OF CONSTRUCTING A PROGRAMMING SYSTEM ORIENTED TO THE DEVELOPMENT OF A PROGRAM PACKAGE FOR SOLVING PROBLEMS IN CONTINUUM MECHANICS

V. D. Malshakov, L. V. Nesterenko, I. D. Sofronov
VANT. Ser.: Mat. Mod. Fiz. Rroc. 1989. No 2. P. 3-8.

      The paper formulates requirements involved in developing integrated machine-independent technology to create a package for solving problems in continuum mechanics. We describe a general structure of basic tools included in a problem-oriented utility, its implementation principles and composition. Our efforts principles are briefly outlined.

V. F. Kuropatenko, G. V. Kovalenko, V. I. Kuznetsowa, G. I. Mikhailova, B. K. Potapkin, G. N. Sapozhnikova
VANT. Ser.: Mat. Mod. Fiz. Rroc. 1989. No 2. P. 9-18.

      We present physical and computational models designed to simulate numerically a nonsteady-state motion of cotinuum with respect to a number of physical processes. A nonhomogeneons difference method is examined for numerical integration of a system of conservation laws. The difference shemes used are explicit. We give difference equation stability conditions and some ways for adapting spatial grids to solutions.

V. F. Kuropatenko, T. E. Eskova, G. V. Kovalenko, V. I. Kuznetsova, G. I. Mikhailova, B. K. Potapkin, Sapozhnikova G.N.
VANT. Ser.: Mat. Mod. Fiz. Rroc. 1989. No 2. P. 19-25.

      We describe a general organization of the VOLNA package designed to simulate numerically a nonsteady-state motion of continuum with respect to a number of physical processes. Package architecture, input and output data, data file structure, development and operation principles are described.

A. S. Kisel, V. A. Kubyak, V. I. Legonkov, A. M. Yaroshevsky
VANT. Ser.: Mat. Mod. Fiz. Rroc. 1989. No 2. P. 26-36.

      The paper describes the implementation of a modular/structural programming system (MOST) in the PDO OS SVM on- the ES computer which was designed for automating large application program development based on a modular/structurai approach. This approach assumes problem and algorithm decomposition into separate components (modules) having appropriate hierarchical relations between them and subsequent gathering these components into a desired structure, represeuting an application program. We focus on module description language, module interface description facilities, module specialization and external particularization.

G. A. Goncharov, V. P. Gorelov, A. N. Grebennikov, E. V. Malinovskaya, Yu. V. Petrov, G. G. Farafontov, V. F. Yudintsev
VANT. Ser.: Mat. Mod. Fiz. Rroc. 1989. No 2. P. 37-46.

      Some results on accounting resonance effects in multigroup neutron calculations are presented. Two methods are examined: cross-section self-screening factor and subgroup methods. The ways are discussed for estimating resonance features of the weight function used to obtain cross-section resonance self-screening factors. The paper considers a more cost-effective method for accounting resonance effects which is involved in group constant setting and assoc i ted with a subgroup method.

M. Yu. Kozmanov
VANT. Ser.: Mat. Mod. Fiz. Rroc. 1989. No 2. P. 47-50.

      Maximum principle and solution existence theorem are given for a system of nonstationary spectral radiation and energy transport equations with respect to anisotropic scattering.
      The system of integrodifferential equations under consideration is nonlinear and contains improper integrals. The solution is proved to exist for any restricted time interval.

M. Yu. Kozmanov
VANT. Ser.: Mat. Mod. Fiz. Rroc. 1989. No 2. P. 51-54.

      The paper formulates sufficient conditions of monotonicity in one class of difference schemes for a system of radiation transport equations. Several ways for increasing difference scheme accuracies are considered.

M. Ya. Ivanov, R. Z. Nigmatullin
VANT. Ser.: Mat. Mod. Fiz. Rroc. 1989. No 2. P. 55-64.

      We describe some features of a second-order accuracy implicit difference scheme designed to numerically solve a system of Euler equations. The scheme relies upon the main ideas included in the well-known explicit Godunov scheme, that is mono- tonicity generalized the varying coefficient case and the Riemann problem accounting local flow structure. The scheme is three-layered in time axis and uses piecewise parabolic distributions of characteristic variables over the difference mesh cells. We give cal-culational results for subsonic, transsonic, and supersonic flows of inviscid and nonconducting gas in nozzles, channels, turbine and compressor grills.

V. V. Basharov, S. K. Buruchenko
VANT. Ser.: Mat. Mod. Fiz. Rroc. 1989. No 2. P. 65-69.

      We examine elastic-plastic bodies impacting deformable and rigid targets with velocities ranging from 130 tens to hundreds m/sek. The Lagrange expilicit tinite-element method is used to solve the problem. For a number of problems, our results are compared with those obtained from other calculations.
      The problems described have the following i important features: strong deformation, 3-D motion due to impacts, contact surface formation and elimination (variability) on interacting bodies.

N. P. VeIdyaksov
VANT. Ser.: Mat. Mod. Fiz. Rroc. 1989. No 2. P. 70-75.

      The paper describes macros extending Macro-11 Assembler capabilities for data structuring and description. Data structures are described by macro- instructions. Complicated structures are constructed hierarchicably buy introducing existing structures as their components. These are referenced with unique data structure names similar to predefined data type references in Pascal. Simple (number, symbol, logic) and complex (sets, files, records) data structures are allowed. Both conventional and optional records are possible.
      It is also possible to have various file and record superpositions. Several macroinstructions are developed to process data structures. Input data may be specified both in design and run-time stages.

A. S. Shvedov
VANT. Ser.: Mat. Mod. Fiz. Rroc. 1989. No 2. P. 76-77.

      Typically, boundary conditions are reproduced as accurately as possible to discretize boundaryvalue problems in computational physics. This note contains an example which shows that distorting boundary conditions in a discretized model may improve calculational results, of course, this distorting should not affect the difference sheme approximation order.

E. I. Cherepanova, V. М. Shmakov
VANT. Ser.: Mat. Mod. Fiz. Rroc. 1989. No 2. P. 78-79.

      ENDL libraries and their format for representing neutron data are commonly used in domestic computational applications. In this connection a program was developed to translate PROM library constants to the ENDL format. While developing this, data types were somewhat extended for the ENDL format, this permitting to obtain more information on neutron-material interaction nature.