Equivalence of sessile droplet dynamics under periodic and steady electric fields

Kainikkara, Muhamed Ashfak and Pillai, Dipin S. and Sahu, Kirti Chandra (2021) Equivalence of sessile droplet dynamics under periodic and steady electric fields. npj Microgravity, 7 (1). ISSN 2373-8065

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Abstract

The electrohydrodynamics of a sessile droplet under the influence of periodic and steady electric fields in microgravity conditions is theoretically investigated using an inertial lubrication model. Previous studies have revealed that a freely suspended spherical droplet with unequal conductivity and permittivity ratios exhibits distinct dynamics under periodic and equivalent steady forcing in the root mean-square sense. However, it is unclear when (if at all) such distinct dynamics occur for periodic and equivalent steady forcing in the case of sessile droplets. The equivalence between periodic and steady forcing is shown to be governed by the interfacial charge buildup, which further depends on the competition between the charge relaxation and forcing timescales. A circulation-deformation map is introduced for the sessile droplet that acts as a guideline to achieve electric field-induced wetting or dewetting as the case may be. We also demonstrate that a droplet may be rendered either more or less wetting solely by tuning the forcing frequency. © 2021, The Author(s).

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IITH Creators:

IITH Creators	ORCiD
Sahu, Kirti Chandra	http://orcid.org/0000-0002-7357-1141

Item Type:

Article

Additional Information:

We gratefully acknowledge the insightful discussions with Prof. Ranga Narayanan (University of Florida). D.S.P. and K.C.S. also acknowledge support from SERB, India (SRG/2020/00242 and CRG/2020/000507).

Uncontrolled Keywords:

Conductivity ratio; Droplet dynamics; Forcings; Inertial lubrication; Lubrication models; Microgravity conditions; Permittivity ratio; Sessile droplet; Spherical droplets; Unequal conductivities

Subjects:

Chemical Engineering

Divisions:

Department of Chemical Engineering

Depositing User:

. LibTrainee 2021

Date Deposited:

19 Aug 2022 11:45

Last Modified:

19 Aug 2022 11:45

URI:

http://raiithold.iith.ac.in/id/eprint/10233