NUMERICAL DETERMINATION OF AERODYNAMIC COEFFICIENTS USING A GAS HYDRAULIC ANALOGY WATER TABLE

FLOW RESEARCH, INC. (FLOW), PROPOSES TO DEVELOP A SCANNING LASER-SHEET TECHNIQUE AS A SENSING AND TOPOGRAPHIC MAPPING DISPLAY SYSTEM FOR THE MEASUREMENT OF WATER SURFACE DISPLACEMENT. THE PROPOSED TECHNIQUE IS AN EXTENSION OF PROVEN OPTICAL METHODS DEVELOPED AT FLOW FOR MEASURING THE DISPLACEMENT OF CAPILLARY AND BREAKING WAVES. THIS TECHNIQUE IS ESSENTIAL FOR CARRYING OUT THE SHALLOW-WATER HYDRAULIC ANALOGY OF COMPRESSIBLE AERODYNAMIC PHENOMENA, WHICH ARE OTHERWISE TOO COMPLICATED TO BE INVESTIGATED BY NUMERICAL MODELING AND WIND-TUNNEL TESTING. THE PHENOMENON OF SPECIFIC INTEREST OF DOD IS THE SEPARATION OF AN ESCAPE CAPSULE FROM AN AEROSPACE VEHICLE. THE HYDRAULIC ANALOGY WOULD PROVIDE AN INEXPENSIVE OPPORTUNITY TO INVESTIGATE ESCAPE SYSTEM SEPARATION EFFECTS IN TERMS OF MODIFIED AERODYNAMIC COEFFICIENTS FROM LOW SPEEDS TO ABOUT MACH 7. DURING PHASE I, THE FEASIBILITY OF THE PROPOSED SYSTEM, WHICH WILL CONSIST OF OFF-THE-SHELF COMPONENTS, WILL BE DEMONSTRATED THROUGH A SERIES OF EXPERIMENTS CONDUCTED IN A LABORATORY MODEL OF A WATER TABLE INSTALLED IN A TOW TANK. EMPHASIS WILL BE PLACED ON DEMONSTRATING THE SYSTEM'S ABILITY TO SENSE AND DISPLAY THE SURFACE DISPLACEMENT INDUCED BY A TOWED HYDRAULIC MODEL OF THE AEROSPACE VEHICLE.