Electrohydrodynamic-induced interactions between droplets

Das, SK and Dalal, A and Tomar, G (2021) Electrohydrodynamic-induced interactions between droplets. In: Journal of Fluid Mechanics, 915 .

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Abstract

Dispersion of droplets in an emulsion is commonly seen in several chemical, pharmaceutical and petroleum industries. Electric field has been shown to affect the stability of these dispersions. We study the dynamics of a pair of leaky dielectric droplets in a leaky dielectric liquid in the presence of an externally applied electric field. A pair of droplets may coalesce or repel each other in the presence of an electric field. Interactions between a pair of drops have been shown to be governed by the ratio, where and are the ratios of drop to ambient fluid electric permittivities and conductivities, respectively. When inertia is neglected, the droplets approach each other if 1]]>, whereas droplets repel when <!CDATAr/� r. However, inclusion of inertia permits interesting transient behaviour, where the droplets may attract due to the electrostatic dipole-dipole attraction even for <!CDATAr/� r. The approach velocity then is governed by the electrostatic forces and varies as, where is the separation distance between the droplets, in contrast to being hydrodynamically driven as predicted in the Stokes flow limit by Baygents et al. (J. Fluid Mech., vol. 368, 1998, pp. 359-375). For compound droplets, interactions between droplets are essentially governed by the electrical properties of the outer droplet and the ambient fluid. However, transient dynamics may also result in the breakup of a compound droplet and lead to formation of single droplets. © The Author(s), 2021. Published by Cambridge University Press.

Item Type:	Journal Article
Publication:	Journal of Fluid Mechanics
Publisher:	Cambridge University Press
Additional Information:	The copyright for this article belongs to Cambridge University Press
Keywords:	Dielectric liquids; Dispersions; Electrohydrodynamics; Emulsification; Petroleum industry, Approach velocities; Compound droplet; Dipole-dipole attractions; Electric permittivities; Induced interaction; Leaky dielectrics; Separation distances; Transient dynamics, Drop breakup, Trachinotus falcatus
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	21 Apr 2021 07:00
Last Modified:	21 Apr 2021 07:00
URI:	http://eprints.iisc.ac.in/id/eprint/68647

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