Numerical study of shock-wave/turbulent boundary layer interactions on flexible panels with wall-modeled large-eddy simulations

摘要

Coupled fluid structure interaction (FSI) simulations with wall-modeled LES (WMLES) are used to capture the interaction of an oblique shock impinging on the turbulent boundary layer developed along a flexible panel. The simulations replicate prior experiments conducted at the trisonic wind tunnel (TMK) of the Supersonic and Hypersonic Technologies Department at DLR, Cologne. The flow has a freestream Math number M_∞ = 3.0, and an incoming turbulent boundary layer thickness δ_0 = 4 mm upstream of the interaction. It is impinged by an oblique shock generated by a rotating wedge with a maximum deflection angle θ_(max) = 17.5°, reached approximately 15 ms after starting from a zero wedge angle corresponding to a shock-free panel. Displacement signals over time at different panel locations are compared to the experiments and to a previous FSI numerical wall-resolved large-eddy simulation. The effect of flexibility on the wall pressure as a function of streamwise location and time is assessed, showing a modulation by the panel vibration that affects the full panel streamwise extent. Wall pressure power spectral densities show an elongation of the frequency band associated with flow separation region for the flexible case over the nominal rigid configuration. Additionally, the turbulent boundary layer of the flexible panel takes a longer distance to recover downstream of the oblique shock. The peak contribution of the low frequency motions to the power spectrum is increased for the flexible case. The study of separation bubble dynamics reveals that panel flexibility increases the separation length and volume, but leaves the bubble streamwise centroid nearly unaffected.