2008 Volume 56 Issue 658 Pages 530-535
The purpose of the study is to investigate the relevance between the shape of a separated region and phenomena such as transition to turbulence and unsteadiness in hypersonic ramp-induced shock-wave/boundary-layer interaction on the assumption that the latter are influenced by the former. Parametric dependence of the shape based on comparisons between an analytical model and experiments is presented. It is found that the transition threshold value of the flow incidence angle with a ramp surface is reduced as both Reynolds numbers Rexs and Rel increase, where xs and l denote the distance from the leading edge of a flat plate to that of upstream influence and the length of a separated boundary layer, respectively. High speed schlieren images show that the minimum ramp angle at which flowfield unsteadiness is noticed depends on the deviation from the analytical model in shape of a separated region, being slightly larger than the ramp angle where the deviation occurs. It is also shown that the spatial scale of the unsteadiness increases along with an increase in the deviation.
