FLOW SEPARATION CONTROL BY A CONCAVE BUMP

Abstract

The concave bump concept is a passive flow control element to optimize impinging shock-wave/boundarylayer interactions (SWBLI) to a separation free interaction. The concept has been validated experimentally using two canonical wind tunnel models: a two-dimensional (2D) planar model and a 2D axisymmetric model. These models were tested at two Mach numbers and for various shock impingement locations. At the design point the shadowgrams of the flow demonstrated that the bump could suppress the flow separation and the experimental wall pressure distribution matches the theoretically expected shape. Accompanying computational fluid dynamics (CFD) simulations using the DLR TAU code could be validated by the experimental data and attest an improved total pressure recovery. The concept is also applied to a more realistic inlet configuration, a truncated 2D Prandtl-Meyer inlet, where it enables larger total contraction ratios and higher maximum combustion chamber pressures, leading to an increased overall efficiency of the inlet. The findings of this study demonstrate the potential of the concave bump concept for improving the performance of supersonic inlets.