Phase-averaged scanning stereoscopic PIV measurement for classification of vortex regime of synthetic jet in cross flow

A synthetic jet is one of flow control devices that can topologically disturb surrounding flow field by adding periodic injection and suction of surrounding fluid using an oscillating membrane through an orifice. This device can be applied to the downsized fluid machinery without a net mass injection of fluid for the simplified structure. In this study, the phase-averaged three-dimensional flow structures of the synthetic jet in laminar cross flow were measured by the phaselocked scanning stereoscopic PIV. The synthetic jet has a round orifice with a diameter of D = 1.0 mm. Stokes number and dimensionless stroke length were ranged from 6.3 to 12.7 and from 2.67 to 16.0, respectively. Reynolds number of the cross flow based on channel height was 1300. The vortex structure of the synthetic jet in cross flow was drastically changed depending on these parameters. According to the measured 3D vortex structure, the parameter map for the classification of vortex regime was obtained.