Characterization of Corner Plasma Actuators for Pulsed Jet Production

Abstract

The purpose of this investigation is to find the capabilities of the corner plasma actuator when attempting to control separated flow using a pulsed jet. A corner plasma actuator is utilized to force oscillations in the separated shear layer. The practical application of this device is to control the separated flow around aircraft turrets. The goal is to have the ability to create predictable disturbed flow under different flight conditions. To accomplish this task different settings of the actuator will have to be able to adjust to the flow. Three parameters were varied on the actuator. The 5 kHz AC operating voltage to the actuators was modulated at 60, 130, and 200Hz. The operating voltage was set at 6, 8, and 10kV. The duty cycle was adjusted to 20, 35, and 50%. Every combination tested using phase-locked PIV to map the time dependent flowfield over the cycle. Additionally, voltages and current were recorded to calculate power dissipation. The flow results were reduced to combination of an average velocity and a velocity oscillation. These data were collapsed on the dissipated power data and an empirical reduction parameter to provide a calibration for the plasma actuator. Based on the results the velocity at which the corner plasma actuator could provide the flow control desired was estimated to be 8 m/s or less. Nomenclature θ = Momentum thickness U 0 = Freestream Velocity over the step f = Frequency of the instability Re x = Reynolds Number based a distance from leading edge ρ = Density of the air µ = Viscosity of the air V = velocity of the flow from the actuator d = distance particles move dt = change in time cal = calibration of the camera pix_moved = number of pixels that particles moved Dist = distance measured by the ruler Pix = pixels used for calibrating the camera U(variable) = uncertainty of the variable (ex. Ucal)