RAREFIED GAS EFFECTS ON AEROBRAKING/REENTRY VEHICLES WITH WAKES

AEROBRAKING VEHICLES (AOTV, ASTV AND VEHICLES TO MARS) ARE GOING TO MAKE SEVERAL PASSES AND DIP LOW IN THE TRANSITIONAL REGIME IN ORDER TO ACHIEVE THE DESIRED REDUCTION IN VELOCITY. EVEN AT THE LOWEST POINT OF THE TRAJECTORY, SURFACE-SLIP EFFECTS PERSIST AND REAL-GAS EFFECTS DUE TO NONEQUILIBRIUM DISSOCIATION AND IONIZATION SIGNIFICANTLY ALTER THE FLOW STRUCTURE. FURTHER, DUE TO IMPINGEMENT OF THE SHEAR LAYER ON THE VEHICLE PAYLOAD, IT HAS BECOME IMPERATIVE TO INVESTIGATE ACCURATELY THE COMPLETE FLOWFIELD WITH WAKE CLOSURE ON THE VEHICLE IN THE PRESENCE OF SLIP AND REAL-GAS EFFECTS. THIS PROJECT WILL INVESTIGATE THE HYPERSONIC-RAREFIED FLOW PHENOMENA ON A COMPLETE BODY INCLUDING WAKE WITH SLIP AND REAL-GAS EFFECTS FROM THE UPPER RAREFIED REGION TO THE LOWER CONTINUUM REGION OF THE TRANSITIONAL REGIME. THIS WILL BE ACCOMPLISHED BY INCORPORATING IN THE MATHEMATICAL ANALYSIS OF THE NAVIER-STOKES EQUATIONS WITH SLIP, AN ADAPTIVE GRID-GENERATION TECHNIQUE THAT WILL ACCURATELY RESOLVE THE SHOCK STRUCTURE ZONE AND THE HIGHLY VISCOUS REGION NEAR THE SURFACE. IN PHASE I, A SUITABLE, ADAPTIVE-GRID GENERATION TECHNIQUE WILL BE INCORPORATED IN THE MATHEMATICAL MODEL OF THE STAGNATION LINE FLOW. IN PHASE II, THE COMPUTATIONAL ALGORITHM DEVELOPED IN PHASE I WOULD BE APPLIED TO PREDICT THE COMPLETE FLOWFIELD WITH WAKE CLOSURE ON BODIES OF ARBITRARY SHAPE. AEROBRAKING VEHICLES (AOTV, ASTV AND VEHICLES TO MARS) ARE GOING TO MAKE SEVERAL PASSES AND DIP LOW IN THE TRANSITIONAL REGIME IN ORDER TO ACHIEVE THE DESIRED REDUCTION IN VELOCITY. EVEN AT THE LOWEST POINT OF THE TRAJECTORY, SURFACE-SLIP EFFECTS PERSIST AND REAL-GAS EFFECTS DUE TO NONEQUILIBRIUM DISSOCIATION AND IONIZATION SIGNIFICANTLY ALTER THE FLOW STRUCTURE. FURTHER, DUE TO IMPINGEMENT OF THE SHEAR LAYER ON THE VEHICLE PAYLOAD, IT HAS BECOME IMPERATIVE TO INVESTIGATE ACCURATELY THE COMPLETE FLOWFIELD WITH WAKE CLOSURE ON THE VEHICLE IN THE PRESENCE OF SLIP AND REAL-GAS EFFECTS. THIS PROJECT WILL INVESTIGATE THE HYPERSONIC-RAREFIED FLOW PHENOMENA ON A COMPLETE BODY INCLUDING WAKE WITH SLIP AND REAL-GAS EFFECTS FROM THE UPPER RAREFIED REGION TO THE LOWER CONTINUUM REGION OF THE TRANSITIONAL REGIME. THIS WILL BE ACCOMPLISHED BY INCORPORATING IN THE MATHEMATICAL ANALYSIS OF THE NAVIER-STOKES EQUATIONS WITH SLIP, AN ADAPTIVE GRID-GENERATION TECHNIQUE THAT WILL ACCURATELY RESOLVE THE SHOCK STRUCTURE ZONE AND THE HIGHLY VISCOUS REGION NEAR THE SURFACE. IN PHASE I, A SUITABLE, ADAPTIVE-GRID GENERATION TECHNIQUE WILL BE INCORPORATED IN THE MATHEMATICAL MODEL OF THE STAGNATION LINE FLOW. IN PHASE II, THE COMPUTATIONAL ALGORITHM DEVELOPED IN PHASE I WOULD BE APPLIED TO PREDICT THE COMPLETE FLOWFIELD WITH WAKE CLOSURE ON BODIES OF ARBITRARY SHAPE.