Detached Eddy Simulation of Blunt-Fin-Induced Shock-Wave/Boundary-Layer Interaction

Abstract

The unsteady characteristics of shock-wave/boundary-layer interaction induced by a blunt fin in Mach 3 flow were studied using enhanced delayed detached eddy simulation with shear-layer adapted subgrid length scale. The effect of upstream disturbances was explored through the generation of synthetic inflow turbulence via a digital filter approach. Although there was no significant difference with the presence of synthetic inflow turbulence in the mean and root-mean-square fluctuations of the flow primitive variables, differences in the unsteady shock statistics were observed. With synthetic inflow turbulence, the length of the region of intermittent wall pressure fluctuations and the maximum shock zero-crossing frequency were increased. The results were suggestive of a slight increase of the frequency corresponding to peak spectral power of the low-frequency shock position and wall pressure fluctuations. Analysis of cross-correlations and conditional averages showed that the unsteadiness of the downstream separation bubble size was a significant driver of the low-frequency separation shock motion. With synthetic inflow turbulence, the shape of the upstream boundary-layer velocity profile had a significant effect on the high-frequency shock motion. Nevertheless, the results showed some influence of the upstream and downstream flow instabilities on the low- and high-frequency shock unsteadiness, respectively.