STABILITY OF BOUNDARY-LAYER FLOWS OVER CURVED WALLS

The formal analysis of the Gortler-type instability is presented. The boundary-layer equations and the disturbance equations are formulated in a general, orthogonal, curvilinear system of coordinates constructed from the inviscid flow over a curved surface. Effects of the curvature of the wall on the boundary-layer flow are analyzed and are shown to be insignificant for the intended stability analysis. The basic approximation for the disturbance equations is presented and solved numerically. Previous analyses are discussed and compared with the present one. Results show the importance of the boundary-layer growth and are in a good agreement with the experimental data. Effects of suction are introduced and are shown to stabilize the boundary layer.