A MULTICOMPUTER SYSTEM AND ITS PERFORMANCE MODEL FOR CONTINUUM MECHANICS PROBLEMS

I. D. Sofronov, S. P. Belyaev
Vant. Ser. Metodiki i Programmy Chislennogo Resheniya Zadach Matematicheskoy Fiziki. 1983. No 1. P. 3-13.

      The paper studies parallel algorithm development feasibility for solving continuum mechanics problems and the efficiency of its multicomputer inplementa-tion. A problem to be solved is assumed to have as many processors as desired which form a homogeneous computer system running under a general - purpose computer control. For the main classes of difference schemes and a number of irregular grid methods, parallel algorithms, maximum - usage processor number, and potential computation speedup estimates are given.

I. A. Adamskaya, S. P. Belyaev
Vant. Ser. Metodiki i Programmy Chislennogo Resheniya Zadach Matematicheskoy Fiziki. 1983. No 1. P. 14-19.

      Second order equations, invariant with respect to space rotation are considered. A matrix structure with second derivatives is investigated. An explicit matrix form is found.

O. M. Kozyrev
Vant. Ser. Metodiki i Programmy Chislennogo Resheniya Zadach Matematicheskoy Fiziki. 1983. No 1. P. 20-25.

      The paper proposes an algorithm to put together explicit and implicit schemes used for numerical integration of gas dynamics equations across a Lagrangian boundary. An example of acoustic equations shows the scheme stability resulted from putting together two different schemes along with a difference solution convergence to an accurate one. Numerical results are presented.

V. A. Lykov, V. G. Nikolaev
Vant. Ser. Metodiki i Programmy Chislennogo Resheniya Zadach Matematicheskoy Fiziki. 1983. No 1. P. 26-31.

      An analitic solution for a compressed target portion heated by a non - equilibrium corona radiation is obtained. This solution is incorporated into a three-temperature program which allowed also to take into account streaming quantums in a three-temperature approximation. For conventional three - temperature problem computation time, solutions sufficienily close to full spectrum calculations were found. Thus, the approximate method proposed proved to be reasonable for laser target calculations.

Yu. A. Dementiev, R. F. Mashinin, V. F. Mironova, N. N. Chentsov
Vant. Ser. Metodiki i Programmy Chislennogo Resheniya Zadach Matematicheskoy Fiziki. 1983. No 1. P. 32-34.

      The Babayev equation is used to describe a time-dependent thermal radiation transport through a region with a negligibly weak material/radiation interaction in terms of delaying and shadowing effects. The cavity surface is assumed to be composed of several rotation surfaces with respect to a common axis. A calculational grid is mapped onto the cavity surface and the equation is approximated by a system of algebraic equations. The equation coefficients are geometrically considered as angular coefficients and average distances; so their estimations requires four-gold integerals to be calculated over a complex integration region. A procedure for approximate calculation of coefficients relying, when possible, on analytic computations is described.

Ye. S. Andreev, M. Yu. Kozmanov
Vant. Ser. Metodiki i Programmy Chislennogo Resheniya Zadach Matematicheskoy Fiziki. 1983. No 1. P. 35-36.

      The radiation propagation in a fixed medium is considered. Maximum/minimum principle is proved for sys-35 terns of differential and difference equations describing a time-dependent spectral radiation and energy transport. A characteristic method is used to obtain a difference approximation of a system of differential equations. The maximum/minimum principle validity for the difference problem solution shows that uncertainty cannot grow infinitely.

O. B. Feodoritova, N. N. Chentsov
Vant. Ser. Metodiki i Programmy Chislennogo Resheniya Zadach Matematicheskoy Fiziki. 1983. No 1. P. 37-40.

      The following feature is known from the geometrical scattering optics. Suppose, S is a perfectly black spherical surface. If some portion is radiating inward according to the Lambert law, then the rest of the surface has an identical illumunation intensity at any point. This spherical surface feature is proved to be characteristic. In this connection the features of spherical shields, as radiation homogenizators within the simplest ball model surrounded by a shield, are discussed. A possibility to use the optics-geometry dependences analyzed is pointed out.

S. G. Bespoludennov, P. N. Vabishchevich, L. M. Degtyarev, V. V. Drozdov, V. I. Pistunovich
Vant. Ser. Metodiki i Programmy Chislennogo Resheniya Zadach Matematicheskoy Fiziki. 1983. No 1. P. 41-51.

      The calculation of an external magnetic field generated by circular currents to form an equilibrium plasma configuration having preset features is considered. The currents are found from the condition of plasma boundary proximity to a given one and that of mgnetic fluxes frozen in the plasma. A technique for solving a self-consistent problem in external fields relies on variable conversion. The calculational results for the INTOR poloidal megnetic field are given.

V. V. Bashurov
Vant. Ser. Metodiki i Programmy Chislennogo Resheniya Zadach Matematicheskoy Fiziki. 1983. No 1. P. 52-56.

      The calculation of ground mot-ion generated by a punch covered with a thin cylinder shell is studied. Direct solution of such a problem using the VULCAN finite-difference scheme is shown to be cost-ineffective. It is proposed to replace the shell by a normal stress boundary condition resulting from an analysis of a thin elastic-plastic shell behavior under loading.

A. I. Zuyev, N. G. Karlykhanov
Vant. Ser. Metodiki i Programmy Chislennogo Resheniya Zadach Matematicheskoy Fiziki. 1983. No 1. P. 57-60.

      A method for solving equations governing the energy transfer by thermal radiation in combination with electron and ion heat conduction is presented. The thermal radiation is represented by a spectral diffusion approximation. The performance of the method proposed and that of its modifications are illustrated by some test computations. The method can be used to solve radiation gas dynamics equations with a complicated heat transfer.

N. M. Barysheva, G. V. Sinko
Vant. Ser. Metodiki i Programmy Chislennogo Resheniya Zadach Matematicheskoy Fiziki. 1983. No 1. P. 61-62.

      Some results of the aluminium and iron Hugoniot adiabat calculations using a self-consistent field method with local exchange are given. Several features of adiabat behavior arising when taking into account the shell effects are discussed. Iron is recommended as a reference material for tests associated with relative compressibility at superhigh pressures.

A. P. Kuclaev
Vant. Ser. Metodiki i Programmy Chislennogo Resheniya Zadach Matematicheskoy Fiziki. 1983. No 1. P. 63-68.

      The paper considers the main criteria of an information retrieval and output in response to a facto- graphic information reference system user request. The concepts for using logic sense matching criteria in a factographic system are developed. Some examples are given which illustrate request variations within system-user interaction process in iterative mode.