ABSTRAKT

A high pressure transverse air jet is injected into a Mach 5 supersonic model inlet to induce inlet unstart. Planar laser Rayleigh scattering from condensed CO₂ particles is used to visualize flow dynamics during the unstart process, while in some cases, wall pressure traces are simultaneously recorded. Boundary layer separation triggered by downstream surface pressure rise is found to precede the formation of a shock system, instantly followed by inlet unstart. Studies conducted over a range of initial inlet flow conditions reveal that the presence of turbulent wall boundary layers affects the unstart dynamics. It is found that relatively thick turbulent boundary layers facilitate faster inlet unstart, when compared to thin, laminar boundary layers.