Kinematics of vortex ring generated by a drop upon impacting a liquid pool

Abhishek Saha, Yanju Wei, Xiaoyu Tang, Chung K. Law

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


We herein report an experimental study on the morphological evolution of a vortex ring formed inside a liquid pool after it is impacted and penetrated by a coalescing drop of the same liquid. The dynamics of the penetrating vortex ring along with the deformation of the pool surface has been captured using simultaneous high-speed laser induced fluorescence and shadowgraph techniques. It is identified that the motion of such a vortex ring can be divided into three stages, during which inertial, capillary and viscous effects alternatingly play dominant roles to modulate the penetration process, resulting in linear, non-monotonic and decelerating motion in these three stages respectively. Furthermore, we also evaluate the relevant time and length scales of these three stages and subsequently propose a unified description of the downward motion of the penetrating vortex ring. Finally, we use the experimental data for a range of drop diameters and impact speeds to validate the proposed scaling.

Original languageEnglish (US)
Pages (from-to)842-853
Number of pages12
JournalJournal of Fluid Mechanics
StatePublished - Sep 25 2019
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Applied Mathematics


  • breakup/coalescence
  • drops
  • vortex dynamics


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