Volumetric study of a turbulent boundary layer and swept impinging oblique SBLI at Mach 2.3

Abstract: A swept impinging oblique Shock Boundary Layer Interaction (SBLI) is investigated in Mach 2.3 flow induced by a shock generator with x–z plane sweep ψ= 30. 0 ^∘ and x–y plane deflection of θ= 12. 5 ^∘. The incoming flow is a naturally turbulent boundary layer developing over the flat wind tunnel wall with Re _θ= 5600. A combination of Stereoscopic PIV and Tomographic PIV is used to characterize both the undisturbed incoming boundary layer and the resultant complex geometries of the swept SBLI. Linear Stochastic Estimation is used to identify significant boundary layer vortical structures and document changes to their topology at various heights in the boundary layer. Three-dimensional velocity snapshots throughout the swept SBLI show both large-scale growth/collapse of the interaction and prominent streamwise streaks with a notable spanwise periodicity. The time-averaged 3D structure for this configuration is documented for the first time with two scaling zones observed on either side of the incident shock impingement location. In addition to numerous swept features analogous to 2D SBLIs (separation, shear layer, separation bubble, reattachment, etc.), significant unsteadiness in the velocity fields was observed just after reattachment at magnitudes in excess of those encountered in unswept SBLIs suggesting an additional unsteady mechanism is present in the swept configuration. Graphical abstract: [Figure not available: see fulltext.]