Summary of LLNL Russian Projects

Schilling, O

关键词: ALGORITHMS;    APPROXIMATIONS;    BENCHMARKS;    DISTRIBUTION;    EFFICIENCY;    LAWRENCE LIVERMORE NATIONAL LABORATORY;    RADIATION TRANSPORT;    TRANSPORT;   

DOI  :  10.2172/902309
RP-ID  :  UCRL-TR-227384
PID  :  OSTI ID: 902309
Others  :  TRN: US200717%%534

学科分类：物理（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

The objective of this project is to develop and demonstrate more efficient methods for solving radiation transport equations using adaptivity in angle variables. Conventional angular discretization methods require that the angular finite-difference grid be fine enough in any region. If the grid is too coarse, the well-known ''ray effects'' appear. In addition, subdomains appear with a highly anisotropic particle flux distribution over directions (where a very fine angular difference grid must be used), as well as subdomains where the distribution is nearly isotropic. In view of this, a promising approach to multi-dimensional transport solution efficiency enhancement using finite-difference approximations is one employing adaptive grids. Such adaptive methods are expected to resolve the ''ray effect'' problem in a cost-efficient manner. The algorithm for solving the radiation transport equation using an angle-adaptive method with dynamic criteria for constructing the grid was evaluated using a set of benchmark test problems (pipe, slit, vacuum, and spherical).