Dynamics of droplet impacting on a cone

Droplet rebound dynamics on superhydrophobic surfaces has attracted much attention due to its importance in numerous technical applications, such as anti-icing and fluid transportation. It has been demonstrated that changing the macro-structure of the superhydrophobic surface could result in significant change in droplet morphology and hydrodynamics. Here, we conduct both experimental and numerical studies of droplet impacting on a cone and identify three different dynamic phases by changing the impacting conditions, i.e., the Weber number and the cone angle. The spreading and retracting dynamics are studied for each phase. Particularly, it is found that in phase 3, where the droplet leaves the surface as a ring, the contact time is reduced by 54% compared with that of a flat surface. A theoretical model based on energy analysis is developed to get the rebound point in phase 3, which agrees well with the simulation result. Besides, the effect of Weber number and cone angle on the contact time is explored. Finally, the phase diagram of the three phases distribution with We and cone angle is given, which can provide guidance to related applications.