Active control of the wake behind the cylinder

Abstract

Active control of the flow around a circular cylinder using a synthetic jet (SJ) array was experimentally investigated in a small wind tunnel. The prevailing method was flow visualization. Modification of the wake was investigated at two values of a dimensionless momentum coefficient (Cμ = 0.21 and 1.02). Various α and Cf parameters were tested (where α is the angle between SJs and the main flow direction and Cf is the frequency ratio). It was found that the control moves a separation point more downstream, i.e. the width of the wake can be reduced. Moreover, increasing frequency ratio Cf causes refining of the vortex structure. When the SJs are placed at the front or rear stagnation points, the wake tends towards the symmetrical pattern.