Separated flow over a backward-facing step whose height is much greater than the thickness of the lower sublayer of the interaction zone
The flow over a small backward-facing step is considered within the framework of the theory of interaction between a boundary layer and a supersonic flow. The height of the step is assumed to be much greater than the thickness of the lower sublayer of the interaction zone, but much less than the thickness of the boundary layer. At the corresponding limit the flow structure is similar in many respects to that in the well- known Batchelor model. In particular, in the limit the vorticity in the separation zone is constant, and the separation zone is surrounded by a recirculating boundary layer. For an arbitrary value of the vorticity in the separation zone the solutions in the recirculating layer and the separation zone do not match. Reducing the mismatch by varying the vorticity leads to the appearance of secondary separation. The mismatch is fairly small and linear extrapolation makes it possible to obtain a base pressure in satisfactory agreement with experiment.
scientific article; zbMATH DE number 58638