Analysis of Unsteady Behavior in Shock/Turbulent Boundary Layer Interactions with Large-Eddy Simulations

Abstract

Various numerical and physical aspects of shock/turbulent boundary layer interactions (STBLI) are discussed in the context of Large-Eddy Simulations (LES). A spatially developing incoming equilibrium turbulent boundary layer is obtained with a force based tripping mechanism. Previous results are augmented with a detailed analysis of this procedure. In particular, it is shown that relatively coarser meshes may be employed if the strength of the trip is increased, together with an adjustment of the wall thermal condition for a short distance downstream of the trip. This approach yields both adiabatic as well as constant wall temperature results. Additionally, it is shown that precursor events provide estimates for the size of the trip with only a small portion of the domain in the vicinity of the trip, thus yielding an efficient technique. A simulation of a STBLI using this spatially developing incoming turbulent boundary layer confirms the low frequency signal observed in the STBLI by other approaches which use recycling techniques, and reproduces the particular unsteadiness shown in a reference experiment. A detailed analysis is performed of the evolution of the Reynolds stresses through the interaction. The amplification of turbulence energy is quantified, and the evolution of two point correlations is explored. The results indicate that the spanwise decorrelation distance first decreases and then increases through the interaction. A preliminary assessment of the effect of pulsed arc filament based actuators is provided. The results indicate a reduction in the separation length when pulsed at a St corresponding to the peak frequency near the reattachment point.