Mean Flow Similarity Behavior in 3D Shock Boundary Layer Interactions

Shock boundary layer interactions (SBLIs) are prevalent in 3D configurations associated with high-speed inlets and control surfaces. In comparison to canonical 2D interactions, SBLIs generated from swept geometries are poorly understood, particularly regarding the demarcation between various mean flow topologies. Historical studies on 3D SBLIs mean flow have identified cylindrical and conical similarities, with the transition between these states hypothesized to coincide with inviscid shock detachment at an adjusted Mach number, M_slip.  In the current study, 3D compressible N-S equations are used to investigate the mean flow similarity of laminar SBLIs induced by swept impinging oblique shocks and swept compression ramps on flat plates. Results show cases that exhibit quasi-conical features despite being well below the inviscid shock detachment limit, seemingly in contrast to the proposed hypothesis. Quasi-cylindrical features are observed only when the leading edge (LE) of the flat plate is swept. For turbulent flows, preliminary RANS calculations show behavior that is more consistent with past research. The role of the shock generator sweep, deflection, aspect ratio, M_slip, and LE sweep on the mean similarity are studied for both laminar and turbulent cases.