Deformation modes of an oil-water interface under a local electric field: From Taylor cones to surface dimples

Fluidic interfaces disintegrate under sufficiently strong electric fields, leading to electrohydrodynamic (EHD) tip streaming. Taylor cones, which emit charged droplets from the of a conical cusp, are among most prominent and well-studied examples EHD instabilities. In liquid-liquid systems, more complex interface deformation modes than simple cones can be observed, with being pushed away electrode, additional cone structures emerging rim dimple. this article, we investigate mechanisms behind these experimentally numerically, demonstrate that presence triggers dimple at interface. order characterize underlying processes, replace pin electrode by hollow metallic needle prescribed electrolyte volume flow. The submerged electrospray introduces an aqueous KCl solution varying ion concentrations into silicone oils viscosities. By measuring corresponding current optical investigation deformation, study system response variations ionic concentration, viscosity, applied voltage as well flow rate. addition experiments, use finite element solver compute charge transport due in oil phase. Further, potential distribution, field deformation. After calibration our model particle tracking velocimetry data inside phase, reproduce observed summary, work highlights importance for dynamic when is exposed local field.