Flow features of swept shock/turbulent boundary-layer interaction due to a gap beneath a sharp fin

Abstract

A numerical study of the shock/turbulent boundary-layer interaction (STBLI) generated by a sharp fin with a 60deg leading-edge sweep mounted above a flat plate at Mach 2.5 was performed. Incipient separation due to this highly swept fin was determined by varying the fin angle to the incoming freestream. The effect of the fin/plate gap on STBLI incipient separation was established. Sweeping the fin increases the deflection required for incipient separation. Sweeping the fin reduces the interaction strength. A gap causes flow leakage under the fin, further reducing the interaction strength on the windward side. The incipient angle of attack is increased when the gap is large enough. In this study, all gaps investigated produced incipient separation. For the leeward side of the fin, a vortex at the fin leading edge was generated due to the pressure difference across the fin leeward and windward sides. In the cases with gaps, an additional vortex is generated at the fin leading edge and a vortex at the plate surface is also produced. It was found that the effect of the gap is to change the location and shape of these additional vortices.