Study of unsteady characteristics of flare-induced hypersonic shock-wave boundary-layer interaction flowfield with variation in γ

Abstract

ABSTRACTExperimental work has been carried out to study the unsteady flow-field characteristics related to shock-wave/boundary-layer interaction. Tests were carried out on an axisymmetric configuration that has a semi-cone angle of 35° and a flare angle of 20°. Further influence of low γ gases (CO2 and CF4) on the overall interaction process is also investigated. Both surface and off-surface analysis has been carried out. Off-surface study has been made with a laser schlieren system. The purpose of this study was to investigate the source of the unsteadiness related to such interactions. Two types of shock motions, namely, flapping and rippling could be identified for air, the relative importance of each of which is strongly dependent on the location within the interaction and on the type of test gas. Spectral analysis shows the large-scale motion of the separation bubble to be the main source of high amplitude fluctuations. However, the existence of separation bubble itself does not necessarily indicate the prevalence of unsteady flow conditions.