Non-wetting drop dynamics

Abstract

The impact of droplets on solids or weakly-deformable surfaces can lead to non-wetting outcomes, depending on the control parameters. Here, we perform experiments and develop a simple model to understand the impact dynamics by varying three important drop parameters: the Ohnesorge number $\mathcal{O}h$, the Bond number $\mathcal{B}o$ and the Weber number $\mathcal{W}e$. The model suggests that the droplet dynamics is captured by only two non-dimensional groups, namely $\mathcal{O}h$ and $\xi =\mathcal{B}o/\sqrt{\mathcal{W}e}$. For $\xi \ll 1$, the droplet dynamics is fully dominated by $\mathcal{O}h$, but for $\xi \gg 1$, the dynamics depends both on $\mathcal{O}h$ and $\xi$. While the model results show some discrepancies for small $\mathcal{O}h$, they are in very good agreement with the experiments for moderately large $\mathcal{O}h$. The work thereby offers an elaborate description of the droplet impact dynamics in a non-wetting scenario.

arXiv commentThe manuscript was prematurely submitted by me (first author, Lakshman), without the consent of any of the other co-authors

References in corpus (9)

• Drop Splashing on a Dry Smooth Surface
• Water spring: a model for bouncing drops
• Skating on a Film of Air: Drops Impacting on a Surface
• Direct measurements of air layer profiles under impacting droplets using high-speed color interferometry
• Ultrafast Interference Imaging of Air in Splashing Dynamics
• Universal mechanism for air entrainment during liquid impact
• Deformation and relaxation of viscous thin films under bouncing drops
• Dimple drainage before the coalescence of a droplet deposited on a smooth substrate
• Droplet settling on solids coated with a soft layer