Abstract
The condition of the optimal vortex ring formation induced by pulsating jet flow is investigated experimentally by PIV to estimate the vortex core circulation and size. The waveform of a pulsating jet flow is performed by cosine curves. In the pulsating jet flow conditions, the formation condition of the optimal vortex ring is changed widely from the condition proposed by Gharib, so it is difficult to apply Gharib's condition to pulsating vortex ring. The formation time of the optimal vortex ring can be estimated independent of the pulsating conditions if using the condition, proposed in this paper, which the optimal vortex ring is formed when the propagation velocity of vortex core is equal to the convection velocity of shear layer of jet flow.
