一次元垂直衝撃波のDSMC解析における分子間衝突法に関する研究

（第2報　セル内分子数と平均自由行程）

抄録

The direct simulation Monte Carlo (DSMC) method using the improved collision scheme (U-system) has been verified to be effective for one-dimensional normal shock wave that includes extreme non-equilibrium over the whole region of the wave, even with the use of a rough cell-network in the previous paper. The purpose of this study is to investigate a bad influence of a very small number of molecules in a cell on the DSMC analysis of the one-dimensional normal shock wave. The paper also studies the mean free path that restricts cell dimensions in the DSMC method. The effective mean free path measured by a moving distance between a series of collisions of one molecule is verified to become larger than the defined mean free path on the condition that the flow has a large velocity.