2022/11/20 by Leyun Feng, Feng, Leyun, Youhua Jiang +9
Engineering · Materials Science · #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Fluid Dynamics and Heat Transfer #Modular Robots and Swarm Intelligence #Soft Condensed Matter (cond-mat.soft) #Surface Modification and Superhydrophobicity
paper · pdf · doi:10.48550/arxiv.2211.11094
openalex publication_date 2022/11/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Droplets coalescing on flat surfaces tend to end up with the smaller droplet migrating into the larger one. We report a counter-intuitive droplet coalescence pattern on a superhydrophilic cylindrical wire, where the larger droplet is pulled toward the smaller one. Consequently, the center of the combined mass significantly moves toward, often beyond, the original location of the smaller droplet. This phenomenon occurs primarily because the viscous friction that a droplet experiences on a cylindrical wire is not positively correlated with the size of the droplet, unlike the droplets coalescing on flat surfaces. We conducted a dimensional analysis based on a mass-spring-damper (MSD) model. Our model predicts a variety of coalescence patterns as a function of the ratio between droplet sizes, and the prediction matches the experimental observation.