MEASUREMENTS

THE PROBING OF BOUNDARY LAYERS, WAKES, AND SEPARATED FLOWS WITH PHYSICAL PROBES ALMOST ALWAYS LEADS TO QUESTIONABLE RESULTS BECAUSE OF THE INTERFERENCE WITH THE FLOW. APPLICATION OF NONINTRUSIVE OPTICAL PROBES TO MAKE SUCH MEASUREMENTS HAS LED TO IMPORTANT NEW INSIGHTS IN AERODYANMIC FLOWS. RECENT DEVELOPMENTS IN ULTRA HIGH SENSITIVITY INTERFEROMETRY HAVE PRODUCED TECHNIQUES FOR DETECTING BOUNDARY LAYER TRANSITION FROM LAMINAR TO TURBULENT FLOW. EXPERIMENTS SUGGEST THAT SUCH A DEVICE COULD ACTUALLY BE CONFIGURED AND CALIBRATED TO PRODUCE QUANTITATIVE DENSITY INFORMATION COMPARABLE TO HOT WIRE DATA. IT IS PROPOSED TO PERFORM BREADBOARD EXPERIMENTS TO CONFIRM THIS HYPOTHESIS AND TO PROVIDE DESIGN INFORMATION FOR A SYSTEM TO BE APPLIED IN A SELECTED WIND TUNNEL.