Graphics processing unit based direct simulation Monte Carlo

The direct simulation Monte Carlo (DSMC) is a computational method for fluid mechanics simulation in the regime of rarefied gas flow. It is a numerical solution of the Boltzmann equation based on an individual particle basis. Accurate simulations typically require particle numbers in the range of hundreds of thousands to millions. Such large simulations require an inordinate amount of time for processing using serial computing on central processing units (CPUs). In this paper we investigate data-parallel techniques on graphics processing units (GPUs) to execute very large scale DSMC simulations. We have designed and implemented Bird's method on a three-dimensional simulation domain that includes complex geometry interactions. We also have tested and verified the statistical and theoretical accuracy of our implementation. Our results show substantial performance improvements (nearly two orders of magnitude) over Bird's serial implementation without loss of accuracy.