Numerical and experimental study of nominal 2-D Shock-Wave / Turbulent Boundary Layer Interactions

Abstract

Shock-Wave / Turbulent Boundary Layer Interactions (SWTBLI) play an important role in optimizations of supersonic and hypersonic inlets. For over 60 years SWTBLIs have been experimentally and numerically studied. Recently a scaling approach for the characteristic interaction length has been described for two dimensional attached and separated flows. It resulted in a best fit law for a variety of flow conditions. In this study this approach is used to scale a data set of several nominal two dimensional SWTBLIs at Mach 3. The data set is the outcome of an intensive study with variable impinging shock strengths. Cylindrical shock generators with a variable slenderness ratio are mounted at two alternative positions over a flat plate. Experiments and computational fluid dynamic (CFD) simulations have been conducted. The experiments were carried out in the Ludwieg Tube Facility at DLR G¨ottingen, employing Pitot probe measurements, mean wall pressure measurements and the high-speed shadowgraph technique. The Reynolds-averaged NavierStokes (RANS) simulations have been validated with literature studies and by comparing them to experimental results. The CFD results are used to characterize the flow topology. A method is proposed to automatically detect the interaction lengths from shadowgrams. They were used as input for the abovementioned scaling approach which produced a best fit correlation for this experimental setup. Differences to the best fit law from the literature occur by decreasing the cylinder slenderness accompanied by three dimensional effects influencing the interaction region.