NON-INTRUSTIVE TECHNIQUES FOR THE MEASUREMENT OF FLUCTUATING DENSITY, TEMPERATURE, VELOCITY AND SKIN FRICTION IN TURBULENT SUPERSONIC FLOWS

THE MEASUREMENT OF THE HIGH FREQUENCY, FLUCTUATING COMPONENTS OF DENSITY, PRESSURE, TEMPERATURE AND SPECIES CONCENTRATION IN HIGH MACH NUMBER IS NEEDED FOR THE UNDERSTANDING OF TURBULENT FLUID MECHANICS. CURRENT TECHNIQUES FAIL AT HYPERSONIC VELOCITIES BECAUSE OF THE LOW STATIC PRESSURES AND TEMPERATURES AND THE HIGH STAGNATION TEMPERATURE IN THE TEST SECTION. THIS IS AN INNOVATIVE IDEA TO OBTAIN NON-INTRUSIVE DENSITY MEASUREMENTS BASED ON THE SPECTRALLY FILTERED RAYLEIGH SCATTERING (FRS) TECHNIQUES. TO DETERMINE THE FEASIBILITY OF THE FRS TECHNIQUES, A WORK PLAN CONSISTING OF THREE MAJOR TASKS IS PROPOSED. THE FIRST TASK IS MODELING OF DENDITY SENSITIVITY UNDER THE REQUIRED FLOW CONDITIONS. THE SECOND TASK IS A LABORATORY VERIFICATION OF THE LAST TASK IS A DESIGN OF A PROTOTYPE. IF FEASIBILITY IS SHOWN, THE TECHNIQUE WILL BE EXTENDED FOR VELOCITY AND TEMPERATURE MEASUREMENTS. THEN, THE PROPOSED SYSTEM WILL BE CONSTRUCTED AND TESTED AT A GOVERNMENT WIND TUNNELL FACILITY UNDER A PHASE II ACTIVITY. THIS WILL PROVIDE THE ARMY WITH A POWERFUL DIAGNOSTIC METHOD NEEDED FOR THE UNDERSTANDING OF TURBULENT SUPERSONIC FLOWFIELDS AND FOR THE VALIDATION OF CFD CODES.