Collision dynamics and mixing of unequal-size droplets

Dong Liu, Peng Zhang, Chung K. Law, Yincheng Guo

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


A computational study based on a front tracking method was conducted by solving an unsteady, axisymmetric Navier-Stokes equation to investigate the mixing efficiency between two colliding droplets subsequent to their merging. Results show that, for droplets of sufficiently dissimilar sizes, the smaller droplet would transform into a mushroom-shaped jet that penetrates into the interior of the larger droplet, and hence greatly facilitates mixing. The jet acquires its energy from the surface energy of the colliding interfaces that are eliminated upon merging. For droplets of similar sizes, jet formation is not favored due to symmetry, and the eliminated surface energy is rapidly dissipated through viscous action of the droplet internal motion. The results qualitatively agree well with previous experimental observations.

Original languageEnglish (US)
Pages (from-to)421-428
Number of pages8
JournalInternational Journal of Heat and Mass Transfer
Issue number1
StatePublished - Jan 15 2013

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes


  • Droplet collision
  • Front tracking
  • Jet formation
  • Surface energy


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