Vortex Behavior of Vertical and Inclined Synthetic Jets in Cross Flow at Low Reynolds Number

Abstract

An experimental investigation to obtain the three-dimensional flow structure of the synthetic jet in low Reynolds number cross flow has been conducted for the purpose of examining the effective method of vortex generation for flow control. A synthetic jet is a promising technique to promote the mixing and to control the flow separation because it introduces flow perturbation without a net mass injection and the device can be easily downsized. Jet orifice diameter is 0.5 mm, and Reynolds number based on channel height is 650. The phaseaveraged three-dimensional flow structures of synthetic jet with the vertical and the inclined injection patterns were measured by scanning stereoscopic PIV. Then, it becomes clear that both injection patterns generate the hairpin vortex. The inclined injection pattern cannot generate the higher vorticity compared with the vertical one, but it is suitable for the control of flow separation because the hairpin vortex exists near wall region.