Shock Wave Boundary Layer Interaction Measurement Assembly on the EXPERT Capsule

Abstract

In order to improve the level of confidence in the design of one of the most critical technology for re-entry space vehicles, a dedicated flight experiment on the shock wave boundary layer interaction phenomenon to be flown on the EXPERT capsule has been conceived. As matter of fact, the common approach to design a space vehicle is based on ground experimental tests, computational predictions and ground-to-flight extrapolation methodologies even though a modern approach foresees to improve such design tools by validating them with respect to flight experiments. At the moment the lack of hypersonic flight data that can serve as a point of reference for this validation process makes it impossible, especially for some of the most challenging hypersonic problems, as the shock wave boundary layer interaction phenomena that could take place in proximity of a deflected control surface. In the frame of the EXPERT program of the European Space Agency, focused to collect in-flight data on relevant aerothermodynamic phenomena, a certain number of experiments/payloads has been conceived in order to collect flight data for further analysis and comparison with numerical and experimental results. Among the others, the shock wave boundary layer interaction in proximity of two opposite deflected flaps will be analyzed through a dedicated payload in order to consolidate the knowledge on this particular phenomenon. The study of flow separation ahead of the open flap induced by a shock wave boundary layer interaction constitutes payload PL07, currently under investigation: two-symmetrically opposite faces, ahead the 20deg fixed open flaps, will be instrumented with temperature, pressure and heat flux sensors in order to analyze the interaction effects and to characterize the boundary layer approaching the flap. Measurements will be performed along the entire trajectory of representative surface properties to be used to assess the understanding about three dimensional viscous interactions and real gas effects on shock wave boundary layer interaction phenomena in high enthalpy re-entry flow conditions.