The impact of the length-to-depth ratio on aerodynamic surface quantities of a rarefied hypersonic cavity flow

A computational investigation has been carried out to examine a non-reacting rarefied hypersonic flow over cavities by employing the Direct Simulation Monte Carlo (DSMC) method. The work focuses on the effects on the aerodynamic surface quantities due to variations in the cavity length-to-depth (L/H) ratio. The results highlight the sensitivity of the heat transfer, pressure and skin friction coefficients due to changes to the cavity L/H ratio. The L/H ratio ranged from 1 to 4, which corresponds to the transition flow regime based on an overall Knudsen number Kn _L . The analysis showed that the aerodynamic quantities acting on the cavity surface rely on the L/H ratio. It was found that pressure load and heating load to the cavity surfaces presented peak values along the forward face, more precisely in the vicinity of the cavity shoulder. Moreover, these loads are much higher than those found in a smooth surface, for the conditions investigated.