Electrohydrodynamic instabilities of viscous jets under alternating electric fields

Abstract

The instability and breakup of liquid jets under static or alternating electric fields are involved in numerous industrial applications. Unlike under electrostatic fields, far fewer investigations have been conducted to analyze the instability of liquid jets in alternating electric fields. Thus, the electric and viscous correction of viscous potential flow (EVCVPF) is applied here to describe the linear instability of leaky-dielectric liquid jets subjected to alternating electric fields. The effects of alternating electric fields, fluid electric properties, and other parameters are investigated. The capillary instability response is like that of the jets under electrostatic fields. Under a sufficiently strong alternating electric field, the resonance instability dominates surface disturbances, leading to the resonant atomization. Viscous damping makes the resonance weaker–even vanishing with the increasing frequency. Furthermore, the conductive charge–largely dependent on fluid conductivities–has the opposite effect of the surface charge. Thus, when the charge relaxation time approaches the imposed period, the parametric resonance is strongly inhibited. In addition, when aerodynamic effects are sufficiently strong, the resonance is covered.