Validation of a hybrid grid scheme of DSMC in simulating three-dimensional rarefied gas flows

A hybrid grid scheme is employed in a new version of position element algorithm of the direct simulation Monte Carlo (DSMC) method. The computational domain is divided into uniform rectangular grids to track molecular trajectories efficiently, whereas the body surface is described accurately in a style similar to the unstructured grid technique. This scheme has been applied to hypersonic rarefied gas flows past a sphere and impingement of plume on a flat plate. The calculated results are compared with the experimental data of drag coefficients and density distributions along the stagnation line for the case of sphere, and with distributions of pressure, shear stress and heat flux along the plate surface for the case of plume impingement. Good agreement validates the efficiency and accuracy of the scheme in simulating 3-D rarefied gas flows.