Coalescence of drops with mobile interfaces in a quiescent fluid

M. B. Nemer, P. Santoro, X. Chen, J. Bławzdziewicz, M. Loewenberg

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

A study on the axisymmetric near-contact motion of drops with tangentially mobile interfaces under the action of a body force in a quiescent fluid is described. A long-time asymptotic analysis is presented for small-deformation conditions. Under these conditions the drops are nearly spherical, except in the near-contact region, where a flattened thin film forms. According to our analysis, a hydrostatic dome does not form in the near-contact region at long times, in contrast to the assumption underlying all previous analyses of this problem. Instead, the shape of the film in the near-contact region results from the absence of tangential stresses acting on it. As a result, the long-time behaviour of the system is qualitatively different than previously predicted. According to the theory presented herein, the minimum film thickness (rim region) decays with time as hm ~ t-4/5, and the thickness at the centre of the film decays as h0 ~ t- 3/5, which is a faster decay than predicted by prior analyses based on a hydrostatic dome. Numerical thin-film simulations quantitatively confirm the predictions of our small-deformation theory. Boundary-integral simulations of the full two-drop problem suggest that the theory also describes qualitatively the long-time evolution under finite-deformation conditions.

Original languageEnglish
Pages (from-to)471-500
Number of pages30
JournalJournal of Fluid Mechanics
Volume728
DOIs
StatePublished - Aug 10 2013

Keywords

  • Breakup/coalescence
  • Drops
  • Emulsions

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