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Droplet breakup in a stagnation-point flow

Published online by Cambridge University Press:  26 August 2020

Alireza Hooshanginejad
Affiliation:
Department of Mechanical Engineering, University of Minnesota, Minneapolis, ME55455, USA
Cari Dutcher
Affiliation:
Department of Mechanical Engineering, University of Minnesota, Minneapolis, ME55455, USA
Michael J. Shelley
Affiliation:
Center for Computational Biology, Flatiron Institute, Simons Foundation, New York, NY10010, USA Courant Institute of Mathematical Sciences, New York University, New York, NY10012, USA
Sungyon Lee*
Affiliation:
Department of Mechanical Engineering, University of Minnesota, Minneapolis, ME55455, USA
*
Email address for correspondence: sungyon@umn.edu

Abstract

We experimentally and theoretically investigate the dynamics of a partially wetting water droplet subject to a two-dimensional high-speed jet of air blowing perpendicularly to the substrate. When the jet velocity is above a critical value, the droplet evolves under wind and splits into two secondary drops. In addition to droplet splitting, we observe depinning of the droplet on one side when the jet is applied at a small distance from the initial centre of the droplet. In parallel with systematic experiments, we develop a mathematical model to compute the coupled evolution of the droplet and an idealised stagnation-point flow. Our simplified lubrication model yields a criterion for the critical jet velocity, as well as the time scale of the droplet breakup, in qualitative agreement with the experiments.

Type
JFM Papers
Copyright
© The Author(s), 2020. Published by Cambridge University Press

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