一类二维非结构网格DSMC方法的实现策略及其应用

研究了一类二维非结构网格DSMC方法的实现策略。在数据结构方面，设计了局部化的数据组织方式，节约了内存与计算时间。发展了一种跟踪模拟分子迁移的算法，该算法仅需少量的逻辑运算与代数运算，不仅可以快速跟踪模拟分子在网格之间的迁移，而且可以准确判别分子与物面是否相互作用，搜索过程中的附带信息给出了分子与物面碰撞的精确时间与位置，避免了重新计算。引入碰撞距离的思想，既减少存储又保证正确的模拟结果。在程序编制过程中，我们充分展现了Fortran90高级语言的主要特性，引入动态数组、指针、链表以及派生类型数据，编制了计算程序。最后对过渡流域高超声绕流进行了数值试验。

Strategies for implementation of 2D unstructured DSMC method and its application

This paper is to study strategies for implementation of 2D unstructured DSMC method. A data structure based on unstructured mesh is designed to achieve high performance and efficiency. An automatic searching algorithm is presented by calculating intersection point, by which all information about molecules hitting surface can be given. Collision distance is introduced into the unstructured DSMC method, which can avoid restriction that the cell dimension should be of the order of one third of the local mean free path. Dynamic allocation feature of Fortran90 is fully exploited, which makes the code more flexible. Finally, a numerical experiment was made for hypersonic rarefied gas flow past an opening hollow cylinder flare. In some extent, the numerical results confirm the feasibility of the method mentioned above.