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Electro-drop bouncing in low-gravity

Authors :
Mark M. Weislogel
Erin S. Schmidt
Source :
Physics of Fluids. 32:062105
Publication Year :
2020
Publisher :
AIP Publishing, 2020.

Abstract

We investigate the dynamics of spontaneous jumps of water drops from electrically charged nonwetting dielectric substrates during sudden step reductions in the gravity level. In the free-fall environment of a drop tower, the dynamics of drops subject to external electric fields are dominated by the Coulombic force instead of gravity. These forces lead to a drop bouncing behavior similar to well-known terrestrial phenomena though occurring for much larger drops (∼0.5 ml). We provide a one-dimensional model for the phenomenon, its scaling, and asymptotic estimates for drop time-of-flight in two regimes: at short-times close to the substrate when drop inertia balances the Coulombic force due to net free charge and image charges in the dielectric substrate, and at long-times far from the substrate when drop inertia balances free charge Coulombic force and drag. In both regimes, the dimensionless electrostatic Euler number Eu, which is a ratio of inertia to electrostatic force, appears as a key parameter.

Details

ISSN :
10897666 and 10706631
Volume :
32
Database :
OpenAIRE
Journal :
Physics of Fluids
Accession number :
edsair.doi...........baf22278624f28a3b8a40cc6c9eefd40