Laminar flow prior to separation

A boundary layer of an incompressible fluid is analyzed in the region ahead of the point where a free flow line is shed from the surface of a smooth body or from a salient point on the body generatrix. The potential of the external vortex-free velocity field is derived from the theory of the jet flows; it is assumed that the order of magnitude of the initial surface friction may vary over a wide range. It is shown that, in all cases, the boundary layer in the preseparation region allows a unified mathematical treatment, with the initial value of surface friction being one of the parameters.