Electric Discharge Mediated Transient Interfacial Dynamics of a Sessile Liquid Droplet: Plethora of Hydrodynamic Features*

We experimentally demonstrate a plethora of hydrodynamic features namely jetting, crowning, and bursting, engendered from capturing electrical discharge inside a sessile liquid droplet. The intense electrical energy deposited inside the conducting droplet in a capacitor like configuration designed with a pin-type anode and thin dielectric film-coated plate type cathode. The high-speed experiments reveal the formation of thermal bubbles from the electrodes and their subsequent evolution till collapse as the dominant mechanism underlying the rich hydrodynamics of the droplet. By tuning the properties of the liquid droplet and the electric field, we can tune the intensity of the discharge and ensuing bubble dynamics, thereby enabling the transition from one regime to another. The position of the electrode can also be tuned to alter the dynamics of shape evolution. The bursting phenomena result from the high electric field and/or high conductivity of the droplet, producing numerous micron size secondary droplets. The explored regimes, specifically bursting of a liquid droplet, are highly relevant for many industrial applications involving enhanced mass transfer such as spray generation, tissue ablation to name a few.