Mass transport using the series of vortex rings with swirl

Abstract

Behavior of the series of laminar vortex rings with circumferential flow, so-called swirl, were investigated using flow visualization, to evaluate the transport efficiency of the ejected fluid as vortex rings. In this study, the interval time of the vortex ring ejection, the formation number of vortex ring L O /D O (the normalized length of the ejected slug of fluid), and the angular velocity of the ejected fluid  are changed, while the mean ejection velocity is fixed. When vortex rings were generated at a short time interval, independent of L O /D O and , they were broken, and most of the fluid included in them was diffused near the orifice. When the vortex rings with little mutual interference were generated at an appropriate interval time, the breakdown of vortex ring structure is suppressed with moderate swirling flow. In those cases, each vortex ring moves separately for a long distance and the distribution area becomes wider as L O /D O increases.

Recent advancements toward the understanding and control of turbulent flows (Summary of ICJWSF2013)

“…The relation between the circulation of vortex rings, generated by a pulsating jet, and the pulsation conditions is investigated, indicating a specific condition for maximum circulation (Akagi, 2013). The mass transport by vortex rings is investigated experimentally (Naitoh, et al, 2013). The results show that the transport efficiency is increased by moderate swirling.…”