TURBULENT SHEAR STRESS MEASUREMENTS IN HYPERSONIC FLOW

ALTHOUGH EXTENSIVE PROGRESS HAS BEEN MADE IN COMPUTATIONAL FLUID MECHANICS, RELIABLE FLIGHT VEHICLE DESIGNS AND MODIFICATIONS STILL CANNOT BE MADE WITHOUT RECOURSE TO EXTENSIVE WIND TUNNEL TESTING. FUTURE PROGRESS IN THE COMPUTATION OF HYPERSONIC FLOW FIELDS IS RESTRICTED BY THE NEED FOR A RELIABLE TURBULENCE MODELING DATA BASE WHICH COULD BE USED FOR THE DEVELOPMENT OF EMPIRICAL MODELS FOR USE IN NAVIER-STOKES CODES. CURRENTLY, THERE ARE FEW COMPRESSIBLE FLOW MEASURMENTS WHICH COULD BE USED FOR THIS PURPOSE AND, SINCE ADDITIONAL SHEAR STRESS TERMS MAY BE SIGNIFICANT AT HIGH MACH NUMBERS,MODELS BASED ON INCOMPRESSIBLE MEASUREMENTS MAY NOT BE REALISTIC. AN EVALUATION OF THESE ADDITIONAL TERMS WILL REQUIRE NEW EXPERIMENTAL METHODS. THE PURPOSE OF THIS PROPOSAL IS TO DEVELOP A TECHNIQUE WHICH COMBINES THE ADVANTAGES OF HOT WIRE AND LASER VELOCIMETRY FOR THE MEASUREMENT OF THE SHEAR STRESS TERMS IN HYPERSONIC FLOW.