77th Annual Meeting of the APS Division of Fluid Dynamics (November 24, 2024 — November 26, 2024)

V2691174: Complete, partial, and non-coalescence of sessile droplets on superhydrophobic surfaces

Authors

• Gopal Pal, Indian Institute of Technology Ropar
• Chander S. Sharma, Thermofluidics Research Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Ropar, Rupnagar, Punjab 140 001, India
• Cheuk Wing Edmond Lam, Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA

DOI: https://doi.org/10.1103/APS.DFD.2024.GFM.V2691174

When multiple droplets are located in close vicinity on a surface, the coalescence of two droplets in the cluster can trigger a chain of coalescence events involving the rest of the droplets. Such multi-droplet coalescence is commonly observed during dropwise condensation on water-repellent surfaces. Here, we observe that all droplets participating in such events may not always coalesce, even when the evolving surface of two coalescing sessile droplets reaches a third droplet. The third droplet may coalesce completely, partially, or even bounce off with high lateral momentum. Such disparate outcomes depend on the relative arrangement of droplets on the surface and can be observed across a range of length scales.