Measurements of the triple shock wave turbulent boundary-layer interaction

A joint experimental and computational study has investigated the flowfield structure created by three crossing oblique shock waves interacting with a turbulent boundary layer, Such an interaction is of practical importance in the design of high-speed sidewall-compression inlets. The interaction is created by a test model consisting of two vertical sharp fins mounted at 15-deg angle of attack to a horizontal flat plate. A third compression surface of 10-deg angle is mounted to the plate between the two vertical fins. The Mach 3.85 flowfield is examined experimentally through kerosene lampblack and planar laser scattering visualizations. The results are used to develop a flowfield model of the interaction structure. This structure is found to consist of a complex wave pattern overlying a viscous separated region. The presence of the 10-deg compression ramp reduces the severity of the boundary-layer separation compared to interactions created by the two fins alone, Additionally, the experimental flowfield data are compared with a computational solution using a modified kappa-epsilon (Rodi) turbulence model. A comparison of the results shows that, despite the complexity of the flowfield, the computed solution does reveal several of the key flow features observed experimentally.