Some aspects of three-dimensional boundary layer flows

Abstract

The equations for laminar boundary layer flow over a general smooth surface in three dimensions are analyzed in a normal coordinate system. The invariance properties of these equations are found using the concept of subtensors. The boundary layer equations are not tensor equations but subtensor equations. Conditions for the Cartesian form of the equations are given and a criterion for no secondary flow is found in terms of the geodesies of the body surface. The displacement effect of the boundary layer is also discussed.