Experiments on Mach-wave interactions in a compressible shear layer

A potential technique for improving the growth rate of compressible shear l ayers is studied, in which a wavy-wall geometry is configured in a confined supersonic shear-layer facility that generates Mach waves in the flowfield , The major objective of this work is to evaluate a numerical model that pr edicts the growth properties of a three-way resonant interaction of these s patial Mach waves with duct acoustic waves and Kelvin-Helmholtz waves excit ed artificially or naturally within the shear layer. Measurements show that a tuned pore tone excitation of Kelvin-Helmholtz waves couples with the wa vy-wall-induced disturbances and duct acoustic waves to produce local shear -layer growth rates that are approximately 50% higher than the natural, smo oth-walled baseline case. The conditions for optimum growth rates are in ge neral concurrence with numerical predictions,In this study the how physics of a compressible shear layer in a wavy-wall environment was investigated w ith mean and fluctuating flowfield measurements, as well as schlieren visua lizations.