Haack, Sarah JoThis thesis shows the time-averaged effect of plasma and synthetic jet actuators on flow over bluff body shapes for delaying flow separation and, therefore, reducing pressure drag. The percentage of pressure drag reduction is used to evaluate the effectiveness of these two unique actuators for varied applied voltage, actuator position and flow velocity on a circular cylinder and 2D extrusion of a rotorcraft tail boom cross section. Two non-dimensional parameters were used to evaluate the effect of the actuators: coefficient of momentum (Cμ) and non-dimensional surface distance between the location of the actuator and the flow separation point (SD). Both actuation techniques beneficially affect the pressure distribution by decreasing the pressure near the location of the actuators and increasing the pressure in the separated flow region. Contour plots displaying the variation of the percentage of drag reduction as Cμ and SD vary illustrate optimal operating conditions based on these parameters.en-USThesisEngineering, Aerospaceactive flow controlplasma actuatorsynthetic jet actuatorcircular cylinderbluff body