Non-parallel Stability Analysis Of Compressible Boundary Layer

In present study, the non-parallel stability of a supersonic boundary layer on a flate plate with Mach number 4.5, and of subsonic boundary layers with Mach number 0.3 is investigated effectively by using parabolized stability equations (PSE). With the coordinate transformation, the finite difference technique is employed in both x-coordinate and y-coordinate, meanwhile the period condition is used in z-coordinate. The iteration of predictor-corrector is used in the marching procedure.The Tollmien-Schlichting (T-S) waves are presented which are comparable with the Linear Stability Theory (LST) and PSE results. From different curves computed by the example, the effects of the non-parallelism are accurately given. Results are quite consistent with available data. It has been proved that PSE method is effective to study the non- parallelism of the boundary layer stability. It indicates that the non-parallelism of two-dimensional disturbance is week, but for three-dimensional disturbance the non-parallelism is strong. It also shows that the non-parallelism becomes more and stronger with the increasing of the spanwise wavenumber.