Plasma Flow Control of Cylinders in a Tandem Configuration

Abstract

The tandem cylinder in cross flow represents a canonical flow field geometry that is relevant to the landing gear noise generation process. In this paper, plasma flow control in the form of dielectric barrier discharge plasma actuators is use to control the tandem cylinder flow field with the objective of reducing unsteady pressure fluctuations on the downstream cylinder. Two types of plasma actuators are applied to the upstream cylinder. These include spanwise-oriented plasma actuators and plasma streamwise vortex generators. Flow control experiments were performed over the Reynolds number range 22,000 € ≤ Re D € ≤ 172,000 and the results obtained at both the lowest and highest Reynolds numbers are reported in this paper. In each case, baseline flow field measurements are compared with those using plasma flow control. Results include, global flow visualization, unsteady pressure measurements on the downstream cylinder and nonintrusive near wake surveys using laser Doppler velocimetry. Both methods of plasma flow control are demonstrated to dramatically reduce pressure fluctuations on the downstream cylinder. Nomenclature C p = pressure coefficient D = Cylinder diameter L = Cylinder streamwise separation distance P s = Surface pressure