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Droplet Coalescence is Initiated by Thermal Motion

Sreehari Perumanath, Matthew K. Borg, Mykyta V. Chubynsky, James E. Sprittles, and Jason M. Reese
Phys. Rev. Lett. 122, 104501 – Published 13 March 2019
Physics logo See Synopsis: Two Nanodrops Zip Together to Form One  
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Abstract

The classical notion of the coalescence of two droplets of the same radius R is that surface tension drives an initially singular flow. In this Letter we show, using molecular dynamics simulations of coalescing water nanodroplets, that after single or multiple bridges form due to the presence of thermal capillary waves, the bridge growth commences in a thermal regime. Here, the bridges expand linearly in time much faster than the viscous-capillary speed due to collective molecular jumps near the bridge fronts. Transition to the classical hydrodynamic regime only occurs once the bridge radius exceeds a thermal length scale lTR.

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  • Received 24 May 2018
  • Revised 11 September 2018

DOI:https://doi.org/10.1103/PhysRevLett.122.104501

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

Published by the American Physical Society

Physics Subject Headings (PhySH)

Fluid Dynamics

Synopsis

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Two Nanodrops Zip Together to Form One  

Published 13 March 2019

Simulations reveal that nanometer-scale droplets merge via a zipping-like action initiated by molecular-sized waves on their surfaces.

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Authors & Affiliations

Sreehari Perumanath1,*, Matthew K. Borg1, Mykyta V. Chubynsky2, James E. Sprittles2, and Jason M. Reese1,†

  • 1School of Engineering, University of Edinburgh, Edinburgh EH9 3FB, United Kingdom
  • 2Mathematics Institute, University of Warwick, Coventry CV4 7AL, United Kingdom

  • *sreehari.dharmapalan@ed.ac.uk
  • jason.reese@ed.ac.uk

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Issue

Vol. 122, Iss. 10 — 15 March 2019

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