Stability of a Laminar Boundary Layer Flowing Along a Concave Surface

Abstract

Görtler instability for incompressible laminar boundary-layer flows over constant curvature concave surfaces is considered. The full linearized disturbance equations are solved by the Galerkin method using Chebyshev polynomials to represent the disturbance functions. Stability curves relating Görtler number, wave number, and vortex amplification for a Blasius mean flow are presented. The effect of streamwise pressure variation is investigated using the Falkner–Skan boundary-layer solutions for the mean flow. The importance of including the normal velocity terms for these flows is shown by their effect on the stability curves. The streamwise velocity distribution in the boundary layer on a 3-m radius of curvature plate was investigated experimentally. The results are compared with the stability curves and predicted disturbance functions.