Evolution of nonlinear transverse perturbations in a boundary layer on a curved surface

The nonlinear evolution of a local transverse perturbation in a boundary layer on a curved surface is analyzed in qualitative terms. In particular, attention is given to one of the possible mechanisms of Goertler vortex formation on concave stationary or convex rotating surfaces and in the regions of boundary layer separation and reattachment. By using the method of matched asymptotic expansions for Navier-Stokes equations, with Re much greater than 1, equations are obtained which describe the evolution of transverse perturbations in a laminar boundary layer on a curved surface. Some properties of these equations are examined.