Physical and computational aspects of shock waves over power-law leading edges

Computations using the direct simulation Monte Carlo (DSMC) method are presented for hypersonic flow on power-law shaped leading edges. The primary aim of this paper is to examine the geometry effect of such leading edges on the shock-wave structure. The sensitivity of the shock-wave shape, shock-wave thickness, and shock-wave standoff distance to shape variations of such leading edges is investigated by using a model that classifies the molecules in three distinct classes: (1) undisturbed freestream, (2) reflected from the boundary, and (3) scattered, i.e., molecules that had been indirectly affected by the presence of the leading edge. The analysis showed that, for power-law shaped leading edge with exponent between 2/3 and 1, the shock wave follows the body shape. It was found that, at the vicinity of the nose, the shock-wave power-law exponent is 1/2. Far from the nose, calculations showed that the shock-wave shape is in surprising qualitative agreement with that predicted by the hypersonic small disturbance theory for the flow conditions considered. (C) 2008 American Institute of Physics.