Electrohydrodynamic Actuators for Propulsion and Flow Control

Thesis (Ph.D.)--University of Washington, 2021Non-thermal plasma (NTP) actuators have been studied in the context of flow control, noise and drag reduction, lift augmentation, and laminar-turbulent transition control. These actuators have the advantages of simple design, fast response time, and easy integration. However, insights into the interaction between Coulombic forces and fluid motion are needed to improve the performance of NTP devices. This dissertation aims to improve the performance of plasma actuators for aerodynamic flow control applications. Several analytical and empirical contributions are described hereafter. First, an analytical model is derived from the first principles for corona discharge-induced thrust. Second, an empirical model was developed for standard two-electrode dielectric barrier discharge (DBD) actuators relating plasma volume, actuation voltage, discharge current, and momentum injection. The third contribution is a novel DC augmented dielectric barrier discharge (DBD – DCA) actuator. The DBD – DCA with negative DC generates two times greater thrust force compared to standard DBD. We also present the effect of electrode shape on the thrust augmentation for DBD – DCA over the linear electrode arrangement. The thrust measured quadruples with sawtooth electrode DBD – DCA with negative DC compared to standard DBD. Fourth, the application of an optimized DBD – DCA actuator on a NACA 0012 airfoil; the actuator performances are evaluated in terms of lift and drag coefficients at low angles of attack. The results suggest that DBD – DCA has the best ability to control an aerial vehicle without moving parts