Implicit large eddy simulation of a supersonic turbulent boundary layer over a compression-expansion ramp

Results of a large-eddy simulation (LES) of a supersonic turbulent boundary layer flow along a compression-expansion ramp configuration are presented. The numerical simulation is directly compared with an available experiment at the same flow conditions. The compression-expansion ramp has a deflection angle of β = 25°. The flow is characterized by a free-stream Mach number of Ma∞ = 2.88 and the Reynolds number based on the incoming boundary layer thickness is Reδ0 = 132840. The Navier Stokes equations for compressible flows are solved on a cartesian collocated grid. About 32.5 × 106 grid points are used to discretize the computational domain. Subgrid scale effects are modeled implicitly by the adaptive local deconvolution method (ALDM). A synthetic inflow-turbulence technique is used, which does not introduce any low frequency into the domain, therefore avoiding any possible interference with the shock/boundary layer interaction system. Statistical samples are gathered over 1000 characteristic time scales δ0/U∞. The numerical data is in good agreement with the experiment in terms of mean surfacepressure distribution, skin-friction, mean velocity profiles, velocity and density fluctuations. The computational results confirm theoretical and experimental results on fluctuationamplification across the interaction region. In the wake of the main shock a shedding of shocklets is observed. Results show the development of Görtler-like vortices in the reattachment region. The LES provide a reliable and detailed flow information, which helped to improve considerably the understanding of shock-boundary-layer interaction.