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Curvature effects on the stability of three-dimensional laminar boundary layers

Thesis/Dissertation ·
OSTI ID:5205040

The linear-stability equations that govern the growth of small periodic disturbances for compressible, three-dimensional laminar boundary layer flow are derived in an orthogonal curvilinear coordinate system. The parallel-flow assumption is utilized in the derivation. The system of equations is solved using a finite-difference scheme similar to that in a current state-of-the-art stability-analysis code, COSAL. The LR method and the inverse Rayleigh iteration procedure are used to calculate the eigenvalues. The stability of the three-dimensional compressible laminar boundary layer including the effects of streamline and surface curvature for flows past swept wings where crossflow type disturbances dominate is calculated. A parametric study is performed varying Reynolds number and sweep angle on an airfoil with a concave cutout in the leading edge region of the lower surface. It is known that convex curvature has a stabilizing effect on the laminar boundary layer. Conversely, concave curvature has a destabilizing effect. The magnitude of these effects for swept wing flows is determined. Non-stationary as well as stationary disturbances are calculated, and the most amplified frequencies are identified.

Research Organization:
Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (USA)
OSTI ID:
5205040
Country of Publication:
United States
Language:
English