Generalized Scaling Analysis of the Separation Zone Induced by Shock Wave–Turbulent Boundary Layer Interactions

Abstract

Shock wave–turbulent boundary layer interaction (SWTBLI) exists widely in the internal and external flow fields of supersonic and hypersonic vehicles, and has a significant influence on the aerodynamic performance. Separation scaling analysis for SWTBLIs has been pursued by researchers for decades. This paper took into consideration the downstream expansion fan to present a generalized scaling analysis of the separation zones induced by three types of interactions—incident SWTBLIs, compression corner SWTBLIs, and normal SWTBLIs. To establish this scaling correlation, SWTBLI flow-field data under the condition of free-stream Ma0 of 3.5 and Rδ of 2.34×105 were simulated numerically. The influence of the expansion fan on the wall pressure distributions and the scaling of the separation zone was analyzed in detail. The size of the separation zone was found to be related closely to the pressure increase at the reattachment point. The scaling of the separation zone and the reattachment pressure increase are rendered dimensionless by the displacement thickness of the incoming boundary layer and the dynamic pressure of the incoming free stream, respectively. The generalized scaling of the separation zone was found to follow a simple power function against the reattachment pressure coefficient. This generalized scaling correlation fits a wide range of published experimental data and numerical simulation results.