Shock-shock interaction on the Reusability Flight Experiment (ReFEx)

Abstract

The Reusablility Flight Experiment (ReFEx) is currently under development at the German Aerospace Center (DLR). A coupled experimental and numerical campaign was carried out to investigate the surface heating on the ReFEx payload geometry consisting of a forebody and canard during reentry. In this way, numerical tools for a post-flight analysis can be preemptively improved where required. Experiments were undertaken at the High Enthalpy Shock Tunnel G¨ottingen (HEG) on a 1:4 scale model with the use of temperature sensitive paint (TSP) on the payload geometry to obtain surface heat flux. The model configuration was varied in angle of attack and canard deflection. A Reynoldsaveraged Navier Stokes (RANS) solver in the DLR-TAU code was used for the numerical simulations. This investigation focused on the shock-shock interaction of the nose bow shock with the leading edge shock of the canards. This resulted in significant surface heat flux along the canard. Larger surface heat fluxes were measured in the experiments for the resulting flow downstream of the interaction on the canard, than obtained from the laminar CFD calculations. This was attributed to transition of the boundary layer within the interaction regions and in the presence of significant adverse pressure gradients. Other flow features along the forebody in the vicinity of the canard were qualitatively matched by the numerical solutions. This work aims to demonstrate the extent to which the numerical and experimental tools assist useful insights into flow phenomena during the return stages of the complex ReFEx payload geometry, and the aspects for which improvements are required.