In a numerical study of Bohzmann model equation, a gas-kinetic finite difference scheme with coupling and iteration is constructed to solve molecular velocity distribution function directly. The parallel strategy is established by using parallel technique of domain decomposition based on variable dependency relation, data communication and parallel expansibility. Gas-kinetic HPF(High Performance Fortran) parallel algorithm is developed to solve three-dimensional problems in various flow regimes. Hypersonic gas flows around a sphere and a spacecraft at various Knudsen numbers, Mach numbers and flying angles are computed at a high performance computer with massive scale HPF parallel. The computational results are in good agreement with experimental and theoretical ones. It is shown that the parallel speed-up increases approximately linearly with the numbers of processors. It indicates high parallel efficiency and expansibility with good load balance and data communication. It suggests that a gas-kinetic parallel algorithm on large scale can be used for three-dimensional complex hypersonic flow problems in various flow regimes.

A technique on generation of unstructured grids for three dimensional complex geomtries is presented.Complex configurations are described by several typical kinds of surface patches.A 3D surface patch is first mapped to a 2D segment,then triangulated using a 2D grid generator based on the advancing front method,and finally mapped back to the original 3D shape.Tetrahedral grids are generated by an advancing front method and smoothed by a nodal relaxation technique and a Deluanay transformation.A mesh refinement technique is also given to obtain more accurate solutions.