Control of the Shear Layer Above a Supersonic Cavity Using Energy Deposition

Abstract

An experimental study was conducted to investigate the effectiveness of pulsed energy deposition as a means of active flow control for the shear layer above a supersonic cavity in the open configuration. The excitation pulse was generated with a Q-switched Nd:YAG laser and was applied as a spanwise oriented line along the leading edge of a cavity. The study was conducted at a freestream Mach number of 1.4 and for a cavity length-to-depth ratio of 5.29. The flowfield was analyzed over a range of delay times from the excitation laser pulse using schlieren photography and particle image velocimetry. Analysis of phase-averaged schlieren images suggested the formation and growth of a coherent large-scale structure (consisting of two adjoining vortices) in the wake of the generated disturbance. This result was confirmed through two-component velocity field data obtained from particle image velocimetry measurements. The velocity information was also used to determine the instantaneous convective velocity and define characteristic scales for the large-scale structure.