Effect of Three-Dimensional Plasma Actuation on the Wake of a Circular Cylinder

Dielectric-barrier discharge plasma actuators were mounted on a circular cylinder in a square wave pattern for active forcing of the cylinder wake. The intermittent spacing of the buried electrodes created a spanwise-modulated blowing profile with a spanwise wavelength of four cylinder diameters, such that three-dimensional instabilities in the wake were targeted for control. Considerable spanwise variation in the wake was achieved with low-power forcing when the actuators were mounted at the location of maximum shear layer receptivity. This spanwise variation was a direct consequence of the difference in the vorticity levels of the shed vortices from the cylinder. High power forcing nearly eliminated vortex shedding, leading to a considerable amount of drag reduction as measured in the intermediate wake.