Experimental investigation of an embedded separated flow region between two supersonic streams

The complex interaction region generated by the separation of two supersonic streams past a finite-thickness base occurs frequendy in high-speed flight and is characteristic of the aft-end flowfield of a powered missile. An experimental investigation was conducted in which a flowfield of this type was modeled in a two-dimensional wind runnel. The data was obtained using Schlieren photography, pressure measurements, and two-component laser Doppler velocimeter (LDV) measurements. The shear layer mixing regions were characterized by initially constant-pressure mixing, by an evolution of velocity profiles from truncated boundary layer shapes to wake-like profiles farther downstream, and by relatively high levels of turbulence. The separated flow region was characterized by large negative velocities and strong interactions with the low-velocity regions of both shear layers. Turbulence intensities and kinematic Reynolds stresses were increased greatly in the latter portions of the two shear layers and in the recompression region. Recovery of the mean velocity field in the redeveloping wake occurred quickly, while the turbulence field remained perturbed to the furthest stream wise location.