Based on the nonlinear Boltzmann model equation, the unified simplified velicity distribution function equation adapted to various flow regimes can be presented. The reduced velocity distribution functions are introduced, the discrete ordinate method is applied to the reduce ddistribution functions, and then the kinetic model equation will be cast into hyperbolic conservation laws form with nonlinear source terms. The time-splitting method and the NND finite difference method are extended to slove them. As a results, a simplified unified kinetic algorithm for the gas dynamical problems form various flow regimes has been developed. To test the rliabiltiy of the present numerical method, the one-dimensional shock-tube problem and the flow past two-dimensional circular cylinder with various Knudsen numbers are simualted. The computations of the related flows indicate that both high resolution of the flw fields and good qualitative agreement with the theoretical, DSMA and experimental results can be obtaiend.
展开▼
