A High-Accuracy Algorithm for Solving Problems of Electrostatics in a Nonhomogeneous Spatially Periodic Dielectric Medium

Doklady Mathematics - A high-accuracy economical iterative method is proposed for calculating the potential and the strength of the electric field in a three-dimensional inhomogeneous spatially...     

Fluorosiloxane sealants

Fluorosiloxane sealants of domestic and foreign production that have found wide application in aircraft engineering are reviewed. Their main performance characteristics and application features are presented.     

Numerical algorithm for solving diffusion-type equations on the basis of multigrid methods

A new numerical algorithm based on multigrid methods is proposed for solving equations of the parabolic type. Theoretical error estimates are obtained for the algorithm as applied to a two-dimensional initial-boundary value model problem for the heat equation. The good accuracy of the algorithm is demonstrated using model problems including ones with discontinuous coefficients. As applied to initial-boundary value problems for diffusion equations, the algorithm yields considerable savings in computational work compared to implicit schemes on fine grids or explicit schemes with a small time step on fine grids. A parallelization scheme is given for the algorithm.     

On Convergence of Finite-Difference Shock-Capturing Schemes in Regions of Shock Waves Influence

Doklady Mathematics - We perform a comparative accuracy study of the Rusanov, CABARETM, and WENO5 difference schemes used to compute the dam break problem for shallow water theory equations. We...     

Numerical Simulation of Evolution of Multimode Initial Perturbations in the Development of Richtmyer-Meshkov Instabilities

Results of two-dimensional and three-dimensional numerical calculations simulating development of multimode initial perturbations of the contact interface between two gases when shock waves pass through it are presented. A method of solving gas-dynamic nonlinear equations is described. The calculations are performed using an HP-712 workstation and a PARSYTEC CC multiprocessing computer system based on 12 processors.     

Results of 2D numerical simulations of subnanosecond iodine laser interaction with an al foil target

This report presents the results of a theoretical study and 2D numerical simulations of the interaction of subnanosecond iodine laser pulses with an Al-foil target. The target and laser parameters correspond to the experimental conditions of the “PERUN” iodine laser facility (IP, Prague: pulse energy <50 J, ∼300 psec, focal spot d ∼100 μm; target: Al foil of thickness 30 μm). The simulations were made by using the two-dimensional Lagrange code “ATLANT” (FIAN-IMM, Moscow). We varied the diameter of the focal spot and studied the dependence of the plasma parameters (temperature, x-ray yield, etc.) on the laser flux density and the diameter of focal spots. The numerical results were compared with experimental data. Published as Preprint No. 38 of the Lebedev Physics Institute (FIAN), Moscow, 1993.     

Relationship between acoustic emission and development of the damage zone in the interlaminar fracture of fiber composites

A study is made of unidirectional carbon-fiber-reinforced composites with both thermosetting and thermoplastic matrices. Experimental data on acoustic emission for unidirectional fiber composites with a crack is presented in the form of an exponential dependence of the number of AE signals on the stress-intensity factor. The increase in the size of the damage zone across the layers of the composite turns out to be linearly dependent on loading time (and, thus, on K_lc), in contrast to the usual quadratic dependence along the layers.Presented at the IX International Conference on the Mechanics of Composite Materials (Riga, October 1995).Institute of High-Molecular-Weight Compounds of the Russian Academy of Sciences (St. Petersburg).Translated from Mekhanika Kompozitnykh Materialov, Vol. 31, No. 6, pp. 792–796, November–December, 1995.