Plasma-based control for laminar-turbulent transition: past experience and future directions

Atmospheric plasma discharges have been proposed as a robust and efficient technique for flow control. Dielectric Bartrier Discharge (DBD) plasma actuators boast a wealth of attractive features such as ease and simplicity of construction, directionality of forcing and fast response time. These particular features render plasma actuators extremely attractive for controlling receptive and naturally unstable flows, typically found in transitional regimes. Precise and deterministic plasma-based control of shear layer instabilities is emerging as a viable route to skin friction drag reduction, separation control and acoustic emission mitigation. In this talk, a summary of recent work on the use of plasma actuators in transition control efforts is presented. Special emphasis is given in a partiular class of transitional flows, namely swept wing boundary layer and the ensuing development of crossflow instabilities. Theoretical and experimental approaches are reviewed and salient features of the interaction are discussed. Particular emphasis is given to the receptivity of these flows to unsteady plasma actuation. Finally future directions in this ongoing field ar ebriefly outlined.