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

We study experimentally and numerically the thinning of Newtonian leaky-dielectric filaments subjected to an axial electric field. We consider moderately viscous liquids with high electrical permittivity. We analyze the influence of the electric field on the formation of satellite droplets from the breakup of the filaments in the experiments. The electric force delays the free surface pinching. Two electrified filaments with the same minimum radius are thin at the same speed regardless of when the voltage is 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. Published under an exclusive license by AIP Publishing.

Automated summary

This study investigates experimentally and numerically the thinning process of Newtonian leaky-dielectric filaments under an axial electric field, as well as the influence of the electric field on the formation of satellite droplets. The electric force delays surface pinching, with polarization stress being identified as a key factor in this delay. Additionally, near the pinching point, hydrodynamic forces dominate filament thinning while the polarization stress becomes subdominant despite its divergence at the finite-time singularity.