Receptivity of Shock Waves to Flow Perturbations

Shock wave interactions with flow perturbations play a central role in high-speed flows. This study develops a linear perturbation framework for analyzing such interactions in nonuniform compressible flows, with particular emphasis on the coupling between shock motion and acoustic and entropy disturbances. The classical shock-interaction analyses of Ribner (1954), which neglect reflected disturbances, and Morkovin (1960), which assumes a uniform post-shock flow, are revisited and compared with the response of a shock ahead of a blunt body, where the post-shock flow is spatially varying. The singular behavior of the shock-generated entropy disturbance in the inviscid limit is treated analytically. The framework is then extended to quasi-one-dimensional configurations representative of dual-mode scramjet engines, incorporating area variation, wall friction, and distributed heat addition. The receptivity of the shock and throat locations to incoming disturbances is quantified over a range of perturbation frequencies. Finally, extensions of the framework to two-dimensional flows are discussed.