Drag and Heat Transfer Effects on Hypersonic Vehicles in Close-Proximity Flight

Abstract

A computational investigation of the drag and heat transfer experienced by multiple trailing (following) vehicles in hypersonic flight is presented. Linear arrays of vehicles in flight at Mach 10 are modeled. Results are presented for both parametric two-dimensional cases and for a three-dimensional case. Drag and heat transfer on trailing vehicles in two-dimensional (five vehicle) arrays, for both powered and unpowered configurations, are shown to reduce progressively from leading vehicle to trailing vehicle such that trailing vehicles can experience less than 30% of the drag and heat transfer experienced by the lead vehicle. The three-dimensional study examines pressure drag effects for generic lifting body/wave-rider configurations in a three vehicle array. Drag due to pressure on the trailing vehicle in such an array falls to approximately 20% of that experienced by the lead vehicle for an unpowered case and to less than 20% for the powered case. The drag and heat transfer reductions are due to the developing slip stream resulting from the successive vehicles, with attendant and progressively increasing reductions in local approach Mach numbers, local approach velocities, and surface pressures experienced by trailing vehicles.