Abstract

Experimental research in the stability and transition of high-speed boundary layers requires repeatable, controlled perturbations and low-noise wind-tunnel facilities. The quiet-flow supersonic-nozzle technology developed by NASA Langley Research Center produces a high-quality Mach-4 flow in the Purdue Quiet-Flow Ludweig Tube.¹ A boundary-layer-perturbation method that does not introduce wakes into the flow is required. That is, a perturbation method that introduces the perturbation without otherwise disturbing the quiet flow with struts, ribbons, or similar structures, is an essential part of boundary layer experiments in a quiet-flow supersonic wind tunnel.

© 1995 Optical Society of America