Investigation of Hypersonic Transitional Shock Wave Boundary-Layer Interactions

Abstract

The control surfaces of hypersonic lifting vehicles are some of the hardest parts to design. The reason for this is the very strong shock wave boundary-layer interactions present in front of the control surface. These interactions cannot only reduce the controllability of the vehicle, but they also cause considerable aerodynamic heating. It can even happen that the heat loads on the control surface exceed those at the stagnation point at the nose of the vehicle. The aerodynamic heating on the control surface is one of the driving aspects of hypersonic vehicle design. This aerodynamic heating is influenced greatly by the state of the boundary-layer. A descending vehicle from space encounters different combinations of atmospheric density and velocity, resulting in a considerable range of Reynolds numbers. This results in a varying boundary-layer state during the descent. A potential peak in aerodynamics heating is found when the boundary-layer is transitioning from laminar to turbulent. The effects of such a transitional shock wave boundary-layer interaction on the flow topology is investigated using various compression ramps on a large flat plate. This creates a shock wave boundary-layer interaction with clear transitional structures. Schlieren imaging is used to get more insight in the separation length, separation angle and growth rate of the transitional structures. Next to that, a Quantitative InfraRed Thermography study is performed to investigate the aerodynamic heating on the compression ramp. Overall, a good overview of the features found in a transitional shock wave boundary-layer interaction is presented.