Flow Separation Associated with 3-D Shock-Boundary Layer Interaction (SBLI)

Abstract

The first goal of this work was to determine the relative importance of two regions of flow separation that are caused by a shock wave boundary layer interaction (SBLI) in a rectangular duct. Separation occurs on both the bottom wall and the sidewall; the areas of these two separated regions were measured and compared. The location where separation first begins was also estimated. Most previous studies of SBLI have focused only on a single wall and have ignored interactions where walls meet at corners. A challenging problem that arose was how to best measure separation of 3-D flow that is sufficiently unsteady that the separation has become intermittent. This required that the probability of separation be measured. Two methods were applied to stereo-PIV velocity data in a SBLI occuring at a rectangular corner region of a Mach 2.75 wind tunnel. Method 1 is called the “h-criterion” and Method 2 is called the AVT (Axial velocity threshold) criterion. These methods are used to detect separation regions and provide a separation map at the interaction region. The importance of the side-wall separation regions versus the centerline separation is clearly evident from the results hence presented.