Droplet dynamic response in low-viscosity fluid subjected to a pulsed electric field and an alternating electric field

Droplet dynamic response in low-viscosity fluid under a pulsed direct-current (DC) electric field and a sinusoidal electric field is investigated by experiments and numerical simulations. The coupled level set and volume of fluid method is employed to capture moving interface and the numerical method is validated by experimental results. This article focuses on the effects of waveform, frequency and initial phase on the dynamic response. The deformation period is identical with the electric period for the pulsed DC electric field but the deformation period is half of the electric period for the sinusoidal electric field. As the frequency increases, the maximum deformation degree D max first climbs steadily to a peak value, then decreases steeply and finally approaches an equilibrium value. The maximum D max appears at f = 50 Hz for the pulsed DC electric field and appears at f = 100 Hz for the sinusoidal electric field according to numerical results. These results are helpful for the optimization of electro-coalescence.