Universality of stretching separation

David Baumgartner, Günter Brenn, Carole Planchette*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


We develop a model to predict the fragmentation limit of drops colliding off-centre. The prediction is excellent over a wide range of liquid properties and it can be used without adjusting any parameter. The so-called stretching separation is attributed to the extension of the merged drop above a critical aspect ratio of 3.25. The evolution of this aspect ratio is influenced by the liquid viscosity and can be interpreted via an energy balance. This approach is then adapted to drop–jet collisions, which we model as consecutive drop–drop collisions. The fragmentation criterion is similar to that observed for drop–drop collisions, while the evolution of the stretched jet aspect ratio is modified to account for the different flow fields and geometry
Original languageEnglish
Article number937, R1
Number of pages11
JournalJournal of Fluid Mechanics
Publication statusPublished - 2022


  • breakup/coalescence
  • capillary flows
  • jets

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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