This paper presents a theoretical investigation of the interactions which occur when a laminar boundary layer on a flat surface encounters an expansive corner followed by a shock or other compressive agency. The method consists basically of two equations; the first relates deflections in the external streamlines to pressure changes and the second relates pressure changes to thickening or thinning of the boundary layer. For simplicity it is assumed that the pressure changes and streamline deflections are small.

A comparison is made with the only available experimental results, under conditions which are far outside the range of applicability of the theory. In these circumstances the agreement between the predicted and experimental pressure distributions is reasonable.