Boundary-Layer Receptivity Due to a Wall Suction and Control of Tollmien-Schlichting Waves

A numerical study of the generation of Tollmein-Schlichting waves due to the interaction between a small free-stream disturbance and a small localized suction slot on an otherwise flat surface has been carried out using finite-difference methods. The nonlinear steady flow is of the viscous-inviscid interactive type while the unsteady disturbed flow is assumed to be governed by the Navier-Stokes equations linearized about this flow. Numerical solutions illustrate the growth of decay of the T-S waves generated by the interaction between the freestream disturbance and the suction slot, depending on the value of the scaled Strouhal number. An important result of this receptivity problem is the numerical determination of the amplitude of the Tollmein-Schlichting waves and the demonstration of the possible active control of the growth of Tollmein-Schlichting waves.