Localized forcing of the two-dimensional boundary layer individual microdischarge in a plasma actuator

An experimental-theoretical study has been performed to investigate the disturbances generated in the boundary layer on a plate by individual microdischarges in a dielectric barrier discharge plasma actuator. It has been shown that disturbances in the near field behind the actuator can be interpreted as nonstationary banded structures which away from the actuator are transformed into a fan of growing Tollmien–Schlichting waves. It has been found that the length of the transition zone in which disturbances of the first type predominate is anomalously great and reaches a value of the order of 100 boundary layer displacement thicknesses. This should be taken into account when analyzing parasitic stochastic disturbances produced by plasma actuators used to control laminar-turbulent transition.