Vortex Interaction of In-Line Synthetic Jets Injected at Difference Phase in Low Reynolds Number Cross Flow

Abstract

Synthetic jets are a promising technique to promote the flow mixing and to prevent flow separation, because they introduce periodic disturbance which is more effective for the flow separation control at low Reynolds number. Synthetic jets are also capable of decreasing a size of the actuator device. An experiment was conducted to study the three-dimensional flow structure and interaction of the two synthetic jets in low Reynolds number cross flow. Jet orifice diameter is 0.5 mm and Reynolds number of the cross flow based on channel height is 650. Stokes number based on the injection condition of synthetic jets is 4.6. The two jets were injected through the two orifices in the in-line configuration at the different injection phase angle where the downstream jet velocity is the same as the upstream one. The phase-averaged three-dimensional flow structure of the two synthetic jets was obtained by a scanning stereoscopic PIV system. Then, it is found that complicated vortex interaction introduces the transverse position reversal of the two jets due to the strong induced velocity by the longitudinal vortices