On the stochastic forcing of the boundary layer by plasma actuators

Turbulence generation by plasma actuator is one of the key barriers on the way of their application as virtual roughness elements in boundary layer transition control. Recent application of these devices for the crossflow instability control has shown that, along with the stationary disturbances creation, they perform a broadband unsteady forcing of the boundary layer, leading to the unwanted excitation of traveling modes. To study the physical mechanisms of this broadband forcing, characterization of the discharge-induced disturbances in a 2D subsonic boundary layer was performed. It has been shown that low-frequency velocity pulsations correlate with the discharge optical emission, i.e. they are caused by stochastic microdischarges dynamics in sDBD.