Effect of an axial electric field on the breakup of a leaky-dielectric liquid filament

TL;DR

This study investigates how an axial electric field influences the breakup of a leaky-dielectric liquid filament, revealing electric field effects on droplet formation and pinching dynamics through experiments and simulations.

Contribution

It provides new insights into the role of polarization stress and electric fields in filament breakup, combining experimental and numerical analysis.

Findings

Electric fields induce satellite droplet formation.

Pinching delay is caused by polarization stress.

Hydrodynamic forces dominate near pinch point.

Abstract

We study experimentally and numerically the thinning of a Newtonian leaky-dielectric filament subject to an axial electric field. We consider moderately viscous liquids with high permittivity. The experiments show that satellite droplets are produced from the breakup of the filaments with high electrical permittivity due to the action of the electric field. Two electrified filaments with the same minimum radius thin at the same speed regardless of when the voltage was applied. The numerical simulations show that the polarization stress is responsible for the pinching delay observed in the experiments. Asymptotically close to the pinching point, the filament pinching is dominated by the diverging hydrodynamic forces. The polarization stress becomes subdominant even if this stress also diverges at this finite-time singularity.