A Fully Concurrent DSMC Implementation with Adaptive Domain Decomposition

Publisher Summary

Direct simulation Monte Carlo method (DSMC) is a particle based gas simulation method in which a computer is used to track simulator molecules. The particles are phenomenological models of the molecules in the real gas being computed. A mesh is used to discretize the flowfield and consequently flows around complex bodies can be simulated if the correct meshing technique is used. The computational load exerted by DSMC on a processor is largely dependent on the number of particles simulated upon it. As the particles are free to move throughout the flowfield, the load across the processor array is unbalanced, at least during some time of the computation, leading to an inefficient use of computational resources. This chapter describes a concurrent implementation of DSMC for the solution of complex gas flows, coupled with an adaptive domain decomposition algorithm for unstructured meshes. An example indicates that use of the dynamic domain decomposition technique significantly increases the parallel efficiency of the DSMC code. A parallel DSMC tool is also described in the chapter, as it utilizes unstructured grids for geometric modeling flexibility and has a modular structure enabling ease of software maintenance and extensibility. A domain decomposition technique is used and the program runs under the single process multiple data (SPMD) paradigm.