Magnetohydrodynamic Plasma Actuators for Stall Alleviation

The objective of the present experimental research is to develop a novel magnetohydrodynamic plasma actuator for aerodynamic flow control, specifically, to alleviate retreating blade stall. The actuator is composed of two parallel rail electrodes embedded chord-wise on the surface of an airfoil. Self-induced electromagnetic fields force a low-voltage, high-current, pulsed arc along the length of the electrodes. The repetitive pulsed arc travels at high velocities, transferring momentum to the surrounding air, creating a high-velocity pulsed air wall jet. To quantify the physical characteristics of the plasma flow, the actuator is surface mounted on a flat plate test article and a cambered airfoil to measure the electrical properties, perform high-speed flow visualization, and measure the flow velocity induced by the plasma discharge. The experimental results demonstrate that the plasma arc requires discharge energies on the order of 300 J per pulse to achieve a peak arc velocity of 100 m/s. Wind tunnel tests on a 14.5 inch chord airfoil section, at a Reynolds number of 4.5 x 105 show a maximum velocity of 32.59 m/s induced by the pulsed arc.