Transition Control in a Three-dimensional Boundary-layer Flow Using Plasma Actuators

The applicability of dielectric barrier discharge plasma actuators for controlling the crossflow-vortex-induced laminar breakdown in a three-dimensional swept-wing-type boundary-layer flow is investigated by means of direct numerical simulation (DNS). The first part of the investigation is aimed at modifying the quasi two-dimensional base flow to weaken primary crossflow (CF) instability, mainly due to a reduction of the basic CF. In the second part, the actuators are used to control the three-dimensional nonlinear disturbance state with large-amplitude steady crossflow vortices (CFVs). It is shown for both methods that the amplitudes of the CFVs and the secondary growth of unsteady modes can be reduced and thus transition to turbulence delayed.