Boundary Layer Transition Control using DBD Plasma Actuators

This paper presents experimental and numerical investigations dealing with 2D boundary-layer transition control on an Onera-D airfoil using Dielectric Barrier Discharge actuators. These actuators generate a non-thermal surface discharge, which induces a momentum addition tangentially and close to the wall. In this case, the ability of this kind of plasma actuators to delay transition has been assessed using both steady and unsteady modes of actuation. On the one hand, wind tunnel investigations are conducted, as well as linear stability analyses, in order to study the effect of a steady operated DBD actuator on boundary-layer stabilization. The results show a maximum transition delay of about 35% of the chord for low free-stream velocity (U∞ = 7 m/s). On the other hand, an experiment has been performed using the unsteady force produced by the DBD actuator, to achieve Active Wave Cancellation in a direct frequency mode. With the help of a closed loop control system, a significant transition delay has been achieved by damping artificially introduced TS waves for free-stream velocities up to U∞ = 20 m/s. This work has been conducted within the framework of the PlasmAero project, funded by the European Commission.