Investigations of the Interaction of Boundary Layer and Shock Waves in Transonic Flow

A discussion is given of the interaction between shock waves and boundary layer and of the formation of shocks in transonic flow, based on measurements of transonic flow past a 12% thick circular arc profile. It is found that: a. The shock wave pattern at a given Mach number can be completely altered by changing the boundary layer. b. Shock waves can interact with a boundary layer in a manner similar to the reflection of a wave from a free jet boundary. Shock waves do not necessarily cause boundary layer separation. c. There exist two types of possible transonic flow past a given symmetrical boundary. One symmetrical about the maximum thickness point and one asymmetrical about this point. The first can be identified with the known symmetrical potential solutions. In this case, recompression begins without a shock wave. The asymmetrical case is characterized by an expansion of the flow up to the shock wave. The shock wave in the symmetrical case is related to the "limiting" line of potential theory, the shock wave in the asymmetrical case to the shock waves occurring in de Laval nozzles.