The behavior of single and twin circular synthetic jets devices is experimentally investigated by using Particle Image Velocimetry (PIV) at a Reynolds number equal to 5,100 and a Strouhal number equal to 0.024. The twin synthetic jets are in phase opposition and different inter-axes distances (l) have been studied. Moreover, several nozzle-to-plate distances (H/D=2, 4, 6, 8 and 10) have been investigated. The twin synthetic jets show an interaction which causes higher time-averaged axial velocities and fluctuations than the single synthetic jet case and lower jet width. The time-averaged turbulent fluctuations show that both the single synthetic jet and the twin synthetic jets have a region characterized by low values of turbulence (potential core-like region). The evolution of the mean and statistics quantities have been described through phase-averaged measurements. High turbulence is observed along the shear layer emanated by the nozzle edge and in the vortex ring core. Also the saddle point behavior has been investigated
