On the near field of single and twin circular synthetic air jets

The flow is characterized with PIV phase averaged measurements. Results for the single synthetic jet are in good agreement with the ones present in the literature and a potential core region is defined for the phase averaged flow field of synthetic jets. Twin circular synthetic jets at jet-axes-distance equal to 3 and 5 diameters show the same behavior with respect to the single circular synthetic jet. Differently, strong interaction effects are seen at jet-axes-distance equal to 1.1 diameters: in particular a double vortex ring structure is visualized. This causes a different velocity distribution in the jet core, higher axial velocities and a lower jet width.