Pulsed-Discharge Flow Control over a Conical Forebody

Duty cycle modulation of the alternating blowing from two opposite facing plasma actuators on the leeward surface near the apex of a cone of semi-apex angle 10o to control the mean lateral force and moment and the flow control mechanism are presented. The pressure distributions over the cone forebody are measured by steady and unsteady pressure-transducers. The experiments are performed in a 3.0 m × 1.6 m open-circuit wind tunnel at wind speed of 20 m/s, 45o angle of attack and Reynolds number of 2 × 10 5 based on the cone base diameter. The measurements of pressure distributions indicate that the bi-stable vortex pattern appears to be shifted in opposite direction when the port or starboard actuator is activated while the other is kept off during the test. The flow control effectiveness is analyzed at various free-stream velocities, angles of attack and pulse frequencies. It is shown that the reduced pulse-repetition frequency based on the local diameter at the plasma actuator equal to one yields the highest effectiveness among the cases considered.