Effects of Sweep on Impinging Oblique Shock-Turbulent Boundary Layer Interaction

Abstract

The characteristics of unswept and swept impinging oblique shock turbulent boundary layer interaction (SBLI) are examined with stereoscopic particle image velocimetry (PIV). This is a continuation of a previous study in which an impinging shock is produced by a 15 degree wedge that is swept at angles of 0, 22.5, and 40 degrees in Mach 2.3 flow. The SBLI is investigated at three spanwise planes. The interaction length is found to decrease with increasing sweep angle across the test matrix. The 22.5 degree and unswept case have cylindrical similarity and the 40 degree interaction appears conical. The present study also includes a mirrored 40 degree wedge which shows that the previous results are not due to a particular sidewall boundary layer. All cases show separated flow in the interaction region and most contain reverse flow that is clearly outside of the measurement uncertainty. Results are compared against literature for swept impinging shocks and compression ramps. Nomenclature u = streamwise velocity U ∞ = free stream velocity M ∞ = free stream Mach number δ = boundary layer thickness (99% of U ∞ ) δ * = displacement thickness (incompressible) θ = momentum thickness (incompressible) H = incompressible shape factor u τ = friction velocity P o = stagnation pressure T o = stagnation temperature Re θ = Reynolds number based on momentum thickness ε L = bias error in the interaction length ε fy = bias error in the measured y-position of the floor L = streamwise SBLI region length, X r -X i X r = streamwise projected reflected shock impingement point X i = streamwise projected primary inviscid shock impingement point in a given plane i x = streamwise coordinate x i * = normalized streamwise coordinate, (x-X o )/L in a given plane i y f = measured y-position of the floor z = normalized global spanwise position, z dim /(wedge span), measured from start of interaction