Analysis of three-dimensional separated flow with the boundary-layer equations

An analysis based on the boundary-layer equations is presented for the prediction of three-dimensional separated flow. In this analysis, the boundary-layer equations are solved with finite difference techniques in four inverse (pressure is unknown) modes. One inverse mode, in which the component of vorticity normal to the surface is specified at the boundary-layer edge, is shown to result in an elliptic system of boundary-layer equations which has departure solutions when solved with a forward marching technique. The accuracy of the present analysis in the other three inverse modes using forward marching techniques is demonstrated for: (1) separated flow over an infinite swept wing which has been rendered three dimensional with a rotated coordinate system; and (2) a three-dimensional separated flow problem analyzed by Smith. The principal conclusion of this paper is that the methodology is now in place to solve the boundary-layer equations for three-dimensional separated flow and hence work should now be focused on the development of three-dimensional viscous-inviscid interaction procedures.