DSMC Simulation of Hypersonic Flows over a Compression Ramp Using Subcell Scheme

摘要

Accurate prediction of the surface properties and the recirculation zonernis very imperative for the design of advanced hypersonic vehicles andrnthermal protection. The objective of this paper is to identify thernpredominant factor affecting the accuracy of the calculation and to proposerna more efficient way to simulate the shock wave/boundary layer interactionrnflow. First, the hypersonic flow over a compression ramp of 35-degree isrncalculated by the parallel direct simulation Monte Carlo (DSMC), and thernresults are compared with the benchmark to get a grid resolution. Then, thernsubcell scheme is implemented and the computational efficiency is highlyrnimproved. It is recommended to use a relatively coarse grid with subcellrnscheme to get a reliable result efficiently in engineering. It also can bernfound that the SOF, which is the ratio of mean collision separation (MCS)rnof the particles to mean free path (MFP), plays an important role in thernaccurate prediction of the recirculation zone, surface pressure and heat fluxrncoefficient. Furthermore, further study show it is not a necessary conditionrnto maintain the SOF value below unity throughout the flow field. Morernattention should be given to the SOF value in the cells close to the wall.