Droplet Impact on Flexible Mesoscale Pillars through Drop Tower Experimentation

Droplet impact on a substrate occurs in technologies such as fog harvesting and water recovery on spacecraft. Modifying the topology of a substrate may drastically change the outcomes of droplet impact and in turn improve the capture efficiency. An investigation into droplet impact on substrates with slender flexible millimetric pillars is carried out. The effects of pillar topology and stiffness on droplet impact and capture phenomena are considered. Pillar deflections are shown to alter the droplet impact as well as final equilibrium configurations. Dynamics of such drop impact are rationalized through drop tower experiments and simple models.