Numerical investigation of swept turbulent shockwave boundary layer interactions

Swept turbulent shockwave boundary layer interactions are common to inlet flows and fin flows among others. Away from the inception region, the interaction can exhibit either conical or cylindrical similarity. The relevant parameters and onset boundaries that determine what similarity occurs are not well understood. As part of a combined experimental (at University of Arizona) and numerical (at New Mexico State University) research project, Reynolds-averaged Navier-Stokes calculations of swept shockwave boundary layer interactions were carried out for different tunnel total pressures, freestream Mach numbers, inviscid pressure rises (impinging shock strength), and shock generator sweep angles. By keeping three parameters constant and varying the remaining parameter, the parameter space is systematically explored. All swept interactions display conical similarity. Flow separation is diminished with increasing sweep angle. The present simulations reveal undulations of the separation line for certain parameter combinations. This behavior is observed beyond a critical Reynolds number and pressure rise magnitude. The effect is attenuated by sweep and Mach number. The undulations are accompanied by owl-face skin-friction line patterns similar to those for stall cells on airfoils in the post-stall regime.