Novel sawtooth dielectric barrier discharge plasma actuator for flow separation control

This paper presents an experimental investigation on the flow control of a stalled NACA 0015 airfoil at a Reynolds number Re = 7.7 × 104 using a sawtooth dielectric barrier discharge plasma actuator. The novel electrode configuration involves two sawtooth-shaped electrodes, which are arranged with opposite sawteeth pointing at each other, resulting in a periodic change in the electrode gap. The sawtooth dielectric barrier discharge plasma actuator is investigated for the first time for flow separation control. The flow structures generated by this actuator are found to depend on the height and width of the sawtooth. The application of this actuator on the airfoil leading edge leads to a delay in the stall angle of attack α by 5 deg and an increase in the maximum lift coefficient CLmax by 9%. Under the same power consumption, the conventional dielectric barrier discharge plasma actuator with straight-edged electrodes achieves a delay in stall α by only 3 deg and an increase in CLmax by about 3%. The difference is found to be linked to the fact that the former generates the streamwise wall jet and the near-wall vortices at the tip and in the trough region of the sawtooth electrode, respectively, whereas the latter produces a streamwise wall jet along the straight-edged electrode.