Abstract:

The boundary layer stability on swept wings is investigated computationally by using three-dimensional compressible laminar stability theory. For a threedime-nsional disturbance wave in a three-dimensional boundary layer, an eigenvalue of an eighth-order system of compressible stability equations is computed by highly efficient correlative two-steps method. Compared with initial-value method used commonly, the two-steps method makes a feature of no eigenvalue guess and rapid rate of convergence, and therefore it is extremely efficient for the computation. The analytical solutions of equations at the outer edge of boundary layers are derived, and the correct asymptotic boundary condition is very important for an exact eigenvalue computation and analysis; spurious unstable modes are avoided by choosing available form of stability equations in the present research. The examples of the laminar-flow-control (LFC) wing and the natural-laminar-flow (NLF) wing are given and used to study typical stability problems of Tollmien-Schlichting(T-S) type disturbance and crossflow (C-F) disturbance on the swept wing. The results are quite consistent with available calculations.

Key words: boundary layers, stability, wings