Dispersion of Multiple Sessile Droplets on Surface by an Airflow

A droplet which is placed on a surface and is exposed to an airflow, can be shed, if the drag force overcomes the droplet's adhesion force. Presence of other sessile droplets, in proximity, changes the drag force, so the minimum airflow velocity required to shed the droplets (UCR) can vary. In this thesis, an experimental study on shedding of the multiple sessile droplets was performed on both hydrophilic and hydrophobic surfaces. The effects of the droplets' arrangement type, and the spacing on UCR were elucidate. For a pair of sessile droplets, a model was proposed to predict the UCR based on droplets' size, spacing, arrangement, and surface wettability. For three, or four sessile droplets arranged in triangle, square, reversed triangle, and diamond configurations, the effects of the droplets' interaction on variation of the UCR, was clarified. A critical value for spacing was determined beyond which multiple sessile droplets shed independently.