Physics of Flow Control in Compression Ramp-Induced SBLI Using Filler Wedges

The effectiveness of triangular filler wedges to control shock-induced separation is studied in a 23° compression corner at M = 2.5. Flow visualizations using schlieren imaging and surface oilflow maps suggest that a filler wedge with a leading angle of 8° and a streamwise length greater than or equal to 2.3 times the incoming boundary layer thickness (δᵢ) almost completely removes the separation. It is found, that the flow at the upstream hinge (the leading edge of the filler wedge) can be affected by the presence of the second hinge (the trailing edge) if the wedge length is below 2.9δᵢ . It is also observed that the flow at the second hinge remains attached even for turn angles up to 15°, indicating the increased resistance of the boundary layer to flow separation after passing through the shock-boundary layer interaction at the first hinge. Two possible mechanisms responsible for this behaviour are proposed.