INVESTIGATION OF HYPERSONIC RAREFIED FLOW ON A SPHERICAL NOSE OF THE AOTV

AEROMANEUVERING AND AEROBRAKING VEHICLES, SUCH AS THE AEROASSISTED ORBITAL TRANSFER VEHICLE (AOTV), WILL MANEUVER AND DECELERATE IN THE UPPER RAREFIED REGIME OF THE ATMOSPHERE. IN THE CASE OF THE AOTV, HYPERSONIC RAREFIED FLOW IN THE SHEAR LAYER FROM THE FOREPART OF THE VEHICLE MAYIMPINGE ON THE PAYLOAD BAY, RESULTING IN EXCESSIVE HEATING AND CONSEQUENT DAMAGE TO THE STRUCTURE. IT IS PROPOSED TO INVESTIGATE THE STRUCTURE OF THE FLOW ON THE ENTIRE VEHICLE TO DETERMINE THE SURFACE QUANTITIES, SUCHAS PRESSURE DISTRIBUTION, SKIN-FRICTION, AND HEAT TRANSFER COEFFICIENTS; AND TO PREDICT THE WAKE CLOSURE AND POSSIBLE IMPINGEMENT OF THE SHEAR LAYER FROM THE FOREPART OF THE VEHICLE ON THE PAYLOAD BAY. THIS PHASE 1 PROPOSAL COVERS THE DEVELOPMENT OF THE PHYSICALAND MATHEMATICAL MODELS OF THE HYPERSONIC RAREFIED FLOW ON THE FOREBODY OF AN AOTV WITH A SPHERICAL FOREBODY. RESULTS FROM PHASE I WILL PROVIDE THE INITIAL CONDITIONS FOR NUMERICALLY INTEGRATING THE GOVERNING EQUATIONS OF THE FLOW IN THE AFT PART OF THE VEHICLE. EFFORTS IN PHASE I AND II WILL BE BASED ON THE NAVIER-STOKES MODEL OF THE FLOW. A METHOD WILL BE DEVELOPED THAT CAN BE USED IN DESIGNS OF