Novel use of AMR Unstructured Grids in DSMC Compressible Flow Simulations

摘要

This work describes the step by step efforts taken in the development of a novel, octree based, highly scalable Direct Simulation Monte Carlo (DSMC) implementation to simulate hypersonic compressible flows at continuum-like conditions. Although an unstructured grid is used to capture high gradients in shock-dominated flows, the methodology is demonstrated to be on a par with a two-level Cartesian implementation, when careful algorith-mics are employed. Near ideal scalability is demonstrated on thousands of distributed CPU processors in a detailed study on domain decomposition to achieve a good load balance and efficient point-to-point communication. Emphasis is given to effective memory management techniques required to handle billions of computational particles and cells on peta-scale clusters. Finally, the capability of the code is demonstrated by applying it to simulate complex shock wave boundary layer interactions on a double wedge configuration at a near-continuum Knudsen number.