Mach number effects on conical surface features of swept shock-wave/boundary-layer interactions

Abstract

An experiment and some computational comparisons are described concerning the shock-wave turbulent boundary-layer interactions generated by sharp fins, with emphasis on Mach number effects. The Mach number range is from 2.5 to 4, and the unit Reynolds number is from 50 to 80 X 106/m. Fin angles are varied from 4 to 22 deg. Surface flow patterns are obtained using a color surface-flow visualization technique. The results show that the "upstream-influence response " in the conical far-field region is a function of the freestream Mach number and the shock strength. A new interpretation of the behavior of the upstream influence with changes of the inviscid shock angle is given. Variations of the interaction response with Mach number are observed to be due almost entirely to the shock strength, and not to compressibility effects on turbulence, over the Mach number range considered. The overall agreement between the experimental and computed interactions is good, though the computation underpredicts the upstream influence line somewhat for the stronger interactions. Nomenclature a,b = constants in power of Re5 in Reynolds number scaling law, Eq. (la) Cf = incoming boundary-layer skin-friction coefficient k\\,k2 = constants in f i v correlation, Eq. (3)