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Home Archives Officers Future meetings Indian Society for Heat and Mass Transfer

ISBN : 978-1-56700-478-6

Proceedings of the 24th National and 2nd International ISHMT-ASTFE Heat and Mass Transfer Conference (IHMTC-2017)
2017, December 27-30 , BITS Pilani, Hyderabad, India


DOI: 10.1615/IHMTC-2017.1020
pages 729-734


When a drop impacts on a dry rigid solid substrate, it can lead to deposition, splashing or bouncing. The fate of drop spreading depends on several factors like wetting characteristics of the surface, droplet inertia, surface tension, viscosity of the drop and the surrounding gas and ambient pressure. In this study, we investigate small scale flows where surface force is comparable to inertia force. In such a limit, the drop upon impacting a super-hydrophobic substrate undergoes a complete rebound. This is due to the surface tension force which works like an elastic spring receding the drop spreading. The drop bouncing dynamics is similar to that of an elastic ball bouncing on a rigid substrate. Due to various losses, we find that the coefficient of restitution is less than unity. Upon carefully inspection, we identify two main sources of energy loss - contact line friction and viscous dissipation during ballistic motion of the drop. A detailed study characterising these dissipation mechanisms is presented. The current study would lead to a better understanding of how drops behave on complex surfaces including elastic surfaces.