3D-PTV Measurements of an Axisymmetric Synthetic Jet

The present study aims to measure the volumetric flow field of a circular synthetic jet using three-dimensional particle tracking velocimetry (3D-PTV). The statistical flow characteristics of the synthetic jet have been discussed using ensemble-averaged velocities and their fluctuations. The 3D-PTV data is compared with the 2D-PIV data for the same formation number. The jet width is different in both cases, which owes to the difference in the orifice configuration in the two measurement cases. The streamwise velocity and root mean square velocity dominates the flow owing to the induced velocity of the vortex rings. The transverse velocity and its fluctuations are more than the vertical velocity and its fluctuation. The time evolution of the circular vortex ring has also been shown for two actuation cycles using isosurfaces plots of the normalized vorticity magnitude, which infers that the induced velocity of the vortex ring remains nearly the same throughout the flow field. The streamwise turbulence decreases along the downstream direction, but the ring loses its coherence in the far field due to persisting vertical and transverse turbulence.