Pressure Gradient Effects on Supersonic Transition over Axisymmetric Bodies at Incidence

Boundary-layer transition on axisymmetric bodies at a nonzero angle of attack in Mach 2 supersonic flow was investigated using experimental measurements and linear stability analysis. Transition over four axisymmetric bodies (namely, the Sears–Haack body, the semi-Sears–Haack body, the straight cone, and the flared cone) with different axial pressure gradients was measured in two different facilities with different unit Reynolds numbers. The semi-Sears–Haack body and flared cone were designed specifically to achieve a broader range of axial pressure distributions. Measurements revealed a dramatic effect of body shape on transition behavior near the leeward plane of symmetry. For a body shape with an adverse pressure gradient (that is, a flared cone), the measured transition patterns show an earlier transition location along the leeward symmetry plane in comparison with the neighboring azimuthal locations. For a nearly zero pressure gradient (that is, the straight cone), such leeward-first transition is ob...