Jet size prediction for bursting bubbles with a compound coating*

The Worthington jet from bursting bubbles can break up into small droplets, transporting chemical and biological contaminants into the atmosphere as aerosols. Although the aerosolization by bubble bursting jet significantly impacts global climate and public health, the influence of the contaminants adsorbed at the bubble surface on the bubble bursting jet remains unclear. Here, we investigate the profound effect of a compound contaminant coating on the jet radius, which deviates from the prediction for jets from bare bubble bursting. We rationalize the deviation of the jet radius by characterizing the excited capillary wave propagation at the air-oil-water interface. We further develop a linearized wave damping model and propose a revised Ohnesorge number with a scaling relation that captures the jet radius reasonably well in a wide range of coating liquid viscosities and thicknesses. Our work not only advances the fundamental understanding for bursting bubbles, but also provides insights to model bursting bubble aerosols in realistic configurations.