LES of shock wave/turbulent boundary layer interaction

Well-resolved Large-Eddy Simulations (LES) are performed in order to investigate flow phenomena and the turbulence structure of the boundary layer along a supersonic compression ramp. The numerical simulations directly reproduce an available experiment. The compression ramp has a deflection angle of β = 25°. The mean free-stream Mach number is M_∞ = 2.95. The Reynolds number based on the incoming boundary-layer thickness is Re_δ0 = 63560 in accordance with the reference experiment. About 18.5 × 10 grid points are used for discretizing the computational domain. For obtaining mean flow and turbulence structure the flow is sampled 1272 times over 703 characteristic time scales. Statistical data are computed from these samples. An analysis of the data shows a good agreement with the experiment in terms of mean quantities and turbulence structure. The computational data confirm theoretical and experimental results on fluctuation-amplification across the interaction region. In the wake of the main shock a shedding of shocklets is observed. The temporal behavior of the coupled shock-separation system agrees well with experimental data. Unlike previous DNS the present simulation data provide indications for a large-scale shock motion. Also evidence for the existence of three-dimensional large-scale stream-wise structures, commonly referred to as Görtler-like vortices, is found.