Length-to-depth ratio effects on flowfield structure of low-density hypersonic cavity flow

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