Abstract: The characteristics of flowfields of synthetic jets with slot-nozzle and hole-nozzle were investigated experimentally by utilizing Particle Image Velocimetry(PIV).The results show that: the formations of the synthetic jets from different-nozzles are the same.During the formation process,the rings of vortexes were generated,developed,broken down and merged together periodically,forming a steady jet within a certain normal distance near the orifice exit.The time-averaged flowfields of the synthetic jets were continuous and steady.However,the slot-nozzle synthetic jet appeared wider than the hole-nozzle synthetic jet with a bigger spreading angle.The velocity profiles of the slot-nozzle synthetic jet along the slot-width and the horizontal hole-nozzle synthetic jet appeared symmetrically and self-similarly.But,the velocity profiles of the slot-nozzle synthetic jet along the slot length direction took on a saddle shape and disappeared with the increase of normal distance from the nozzle.