关键词: 统一计算架构（CUDA）, 图形处理器（GPU）, 直接模拟蒙特卡罗方法（DSMC）, 动态网格DSMC, 并行模拟

Abstract: The direct simulation Monte Carlo (DSMC) method is a powerful computational tool in the field of rarefied gas dynamics. However, there are two main shortages in DSMC method: one is complex gridding processing, the other is large time consumption. The dynamic collision grid DSMC method generates collision grids adaptively according to the flowfield, which overcomes the first shortage. For the other shortage, using compute unified device architecture (CUDA) to write parallel program, the dynamic collision grid DSMC method is ported to graphic processing unit (GPU) to reduce computing time. During the parallel implementation, the main computation is performed on GPU while CPU only deals with the processes of initialization and output. A two-dimensional benchmark problem in different sizes is used to demonstrate the correctness of the parallelization. The results show that 10 times speedup is achieved based on NVIDIA Fermi C2050. For a same case, the performance on NVIDIA newly released Kepler K20 is 1.3~1.6 times higher than that on Fermi C2050.

Key words: compute unified device architecture (CUDA), graphic processing unit (GPU), direct simulation Monte Carlo (DSMC), dynamic collision grid DSMC, parallel simulation