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

Abstract

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.

Electrically modulated relaxation dynamics of pre-stretched droplets post switched-off uniaxial extensional flow

“…The study of electrically-modulated droplet relaxation, thus, can explore the fundamental insights into many microfluidic and biological processes where drops, deformable particles, and cells often experience significant alteration in shear rate as they forced to flow through converging-diverging sections. 51–56 Moreover, physics of relevant capillary-driven problems such as the evolution of filaments or liquid bridge subjected to electric field, similar to that considered in recent study of Rubio et al ., 57 can also be well explicated from the present analysis, resulting in intricate manoeuvring of the resulting dynamics and stringent process control.…”

An experimental study of liquid micro-jets produced with a gas dynamic virtual nozzle under the influence of an electric field

“…It is still unclear whether these narrow connecting jets are part of the former jet or were created due to Rayleigh jetting ( Duft et al, 2003 ). Still, the most probable scenario is that they result due to their delayed recoil associated with the presence of charges ( Rubio et al, 2021 , see their Figures 8–10, 12). To be able to answer this question, the jet breakup has to be captured with a higher frame rate.…”

“…Detail (A) shows the elongated droplet with thin, almost invisible jet connecting the droplet to the jet structure. In detail (B) elongated perturbations are displayed together with an extended thin liquid ligament brought about by the presence of electric charges ( Rubio et al, 2021 ). The image was produced using the following parameters: GFR = 24.7 mg/min, SFR = 1 μl/min, EP = 6 kV, L = 0.47.…”

“…A high temporal resolution is required ( Rubio et al, 2021 ) to reveal the exact breakup mechanisms of the jet. Based on the achieved velocities, the required resolution can be estimated somewhere between 10k and 100k FPS (10 µs–100 µs frame period).…”

“…Any parametrical combination of the EP-SFR-GFR values exhibiting pulsation or detachment under steady boundary conditions would correspond to a globally unstable behavior of the In detail (B) elongated perturbations are displayed together with an extended thin liquid ligament brought about by the presence of electric charges (Rubio et al, 2021). The image was produced using the following parameters: GFR = 24.7 mg/min, SFR = 1 μl/min, EP = 6 kV, L = 0.47.…”