Vortex Behavior of In-line Synthetic Jets in Cross Flow

Abstract

An experimental investigation was conducted to study the three-dimensional flow structure and its interaction of the two synthetic jets in low Reynolds number cross flow. 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. 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 in-line orifices at the different velocity ratio of downstream jet to upstream jet. The phase-averaged three-dimensional flow of the two synthetic jets in in-line configuration was measured by a scanning stereoscopic PIV system. Then, it was found that vortex interaction occurs and circulation of the jets becomes larger with increasing the downstream to upstream jet velocity ratio.