Large-Eddy Simulations of Idealized Shock/Boundary-Layer Interactions with Crossflow

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 very thin precursor separation bubble before the point of true separation that extends for at least one boundary-layer thickness but remains fully within the viscous sublayer. Simulations at different Reynolds numbers show that the flow reattaches after the precursor bubble at sufficiently high Reynolds number.