EXPERIMENTAL INVESTIGATION OF THE FLOW STRUCTURE NEAR A SINGLE WRAPAROUND FIN

The flow structure near a single wraparound fin on a wall-mounted semi cylindrical model was experimentally investigated at Mach 2.8 (Re/l = 18 x 10(6) m(-1)). Detailed mean flow and turbulence measurements were obtained using conventional pressure probes and cross wire hot-film a nemometry at a series of stations near the fin. Large flowfield asymme tries were observed in both mean flow and turbulence measurements aft of the shock/boundary-layer interaction, Measured turbulence intensiti es in the fuselage boundary layer were far greater on the concave side of the fin than on the convex side. On the convex side of the fin, th e turbulence intensity levels were 30% lower than the preinteraction v alues, and on the concave side a 50% increase was observed. Similarly, the Reynolds shear stress levels aft of the fin bow shock decreased o n the convex side of the fin while increasing dramatically on the conc ave side. These results are consistent with the stabilizing and destab ilizing effects of pressure gradient distortion on supersonic boundary layers.