Active Tollmien Schlichting Wave Control with a Membrane Actuator in Compressible Flows

The laminar-turbulent transition on an airfoil can be delayed by active control of Tollmien Schlichting (TS) waves in an early stage of a transitional boundary layer using the superposition principle. The present study compares two sensor types regarding their ability to detect TS-waves at various Mach and Reynolds numbers on a transonic profile. Surface hot wire and the surface hot film sensor signals are used to characterize the flow field on a transonic airfoil model. The results are applied as basis for the active wave control experiments at a chordlength Reynolds number of Rec = 3.9 ·106 (c = 1m) at M ∞ = 0.50 and an angle of attack α = − 1°. Cancellation results of 44% amplitude are presented for a voice coil driven actuator