The effect of crossflow on a canonical shock/boundary-layer interaction

An idealized shock/boundary-layer interaction problem that is two-dimensional in the mean but with a three-component mean velocity field is studied using large-eddy simulations. The problem isolates some aspects of three-dimensionality while avoiding others, and can thus offer insights into the differences between two- and three-dimensional problems. The addition of a crossflow increases the size of the separation bubble quite substantially when normalized by the boundary layer thickness or the momentum thickness, but less substantially when normalized by the displacement thickness. All cases studied are found to have a laminar separation bubble before the point of true separation that extends for at least one boundary layer thickness but remains fully within the viscous sublayer. To within the expected uncertainty, the frequency spectra of the wall pressure fluctuations do not change substantially with the addition of the crossflow, despite the increased size of the separation bubble.