Circular Cylinder Wake Control Using Spatially Distributed Plasma Forcing

Abstract

This work investigates the use of spatially-distributed open-loop forcing for threedimensional control of vortex shedding from a circular cylinder. Force-shaped plasma actuators were used to control the flow, with the aim of reducing drag on a circular cylinder at a Reynolds number of 6500. Traditional approaches to cylinder drag reduction have typically involved two-dimensional forcing of the flow field. Spatially-distributed forcing, however, involves a spanwise modulation of the forcing on the flow. A new configuration of the dielectric-barrier discharge plasma actuator was implemented where the momentum addition could be directed either normal or tangential to the surface, as well as spatially tailored in a spanwise fashion to optimize control efficacy. The actuator configuration enables targeted manipulation of the wake-vortex structure shed from a bluff body. The goal of the flow control blowing profile is to break up the spanwise coherency in the vortex street, thereby promoting phase cancellation between spanwise portions of the wake structure. Wake profile measurements were made at several spanwise locations to evaluate the resulting drag reduction and modification of the wake.