III. The interaction between an oblique shock-wave and a turbulent boundary-layer

Summary Schlieren photographs have been taken to show the reflection of oblique shock-waves of different strengths at the turbulent boundary-layer on the wall of a supersonic wind-tunnel. A weak shock-wave is reflected as a compression followed by an expansion; this is in agreement with Lighthill's theory in which the boundary-layer is replaced by a non-turbulent inviscid layer with the same velocity distribution as a turbulent boundary-layer. For stronger incident shock-waves the reflected wave moves upstream of the incident one to a point where the boundary-layer starts to thicken. Thus the incident and reflected shock-waves cross outside the boundary-layer. Near the point where the incident shock-wave meets the boundary-layer, the rate of growth of the boundary-layer suddenly decreases and an expansion occurs. For very strong shock-waves a Mach type of interaction occurs, with a short normal shock-wave between two intersections. The supersonic wind-tunnel and optical system used for these experiments a...