Lift-off of a conducting sessile drop in an electric field

A conducting drop in partial wetting regime, placed on the lower electrode of a parallel-plate capacitor and surrounded by a dielectric fluid, is considered. The drop, initially flattened by gravity, is elongated by the electrostatic force and possibly lifts-off when a uniform DC electric field is applied. The electrostatic force and the lift-off condition were calculated in two previous articles, respectively, for undeformable and for slightly deformable drops in the absence of gravity (zero Eotvos number). In this paper, numerical models are put to work to study accurately the complex lift-off process resulting from the competition between gravitational, electrical and capillary forces. Large deformations of the drop surface at any value of the Eotvos number may be addressed by such a numerical procedure. Computational results allow assessing the accuracy and limits of previous analytical and asymptotic relations.