ELEVON-ELEVON GAP FLOW IMPINGEMENT

Abstract

The paper presents an experimental and numerical investigation of the unsteady, transitional flow resulting at a cantilever flap configuration of a space vehicle in cold hypersonics. The goal oft the study is to investigate the potential to use an aerodynamic controlled vehicle for an aerobraking manoeuvre when returning from a Moon mission. An experimental investigation is carried out in the high-speed Ludwig tube facility of the Technische Universität Braunschweig, at Mach 6, Reynolds numbers varying frorn 2.4 10⁶ to 1.7 10 ⁷, and supported by numerical solutions obtained with the TAU code of the DLR. The analysis of the experimental and numerical results displays a complex unsteady flow topology at the control surfaces, with severe hot points resulting from shock-shock interaction, shock-boundary layer interaction and jet flow in the gap between the flaps. The resulting jet impingement at the flaps results in heat fluxes which largely surpass the stagnation point heat flux. Such situation becomes more severe as the flow evolves from almost laminar for the low Reynolds number case to transitional at the flaps for the high Reynolds number case. It turns out aerobraking manoeuvres with aerodynamic controlled vehicles should be carefully designed since shock-shock interactions may jeopardizing the whole mission.