Pinch-off Dynamics of the Dripping Mode under an Axial Electric Field

Breakup of electrified droplets is a fascinating phenomenon that is of critical importance to electrohydrodynamic (EHD) printing. However, previous studies predominantly focused on the local pinch-off dynamics of pendant droplets or electrified jets stressed by a radial electric field. Here, we conduct a parametric investigation into the pinching dynamics of the dripping mode under a nonuniform axial electric field with a continuous liquid supply. The two-dimensional axisymmetric computational domain is solved using the arbitrary Lagrangian-Eulerian technique coupled to the leaky-dielectric model. The results of this work highlight the complex interplay among inertial, electric field stress, and charge relaxation kinetics. This intricate interplay is responsible for the pinch-off time, droplet length, thread length, and primary droplet size. Furthermore, we find a notable independence of inertial, electric field strength, and electrical conductivity of the liquid on the scaling law describing droplet pinch-off at low viscosity. These findings may have potential applications in improving electrohydrodynamic printing.