The Optimal Formation Condition of the Axis-Symmetry Cyclic Vortex Rings

The cyclic vortex rings, which are generated cyclically by a pulsating jet, appear to be an effective method for particles and fluids transport. In order to identify the formation conditions of cyclic vortex rings that are optimal for transport, the effect of the formation conditions of cyclic vortex rings, such as the velocity pulsation amplitude, period and acceleration of jet pulsation conditions, and conditions of including intermittent period, on the axis symmetry characteristics of behavior of vortex rings is investigated experimentally. The results indicate that the axis symmetry characteristics of cyclic vortex rings begin to loss by the following four factors, the influence of separated vortex rings, the influence of trailing vortex rings, the influence of trailing vortex rings formed in the previous cycle, and the influence of the cyclic vortex ring formed in the previous cycle. The behavior of cyclic vortex rings can be classified into three types, and is determined by the combination of loss-inducing factors and their individual strengths. We also discuss the formation conditions of cyclic vortex rings that are optimal for transport.