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Gravito-capillary pinning of pendant droplets under wet uneven surfaces
- Source :
- Phys. Rev. Fluids 9, L081601 (2024)
- Publication Year :
- 2024
-
Abstract
- Pendant drops spontaneously appear on the underside of wet surfaces through the Rayleigh-Taylor instability. These droplets have no contact line, they are connected to a thin liquid film with which they exchange liquid and are thus mobile: any perturbation will set them in motion. Here, using experiments, numerical simulations, and theory I show that pendant drops sliding under a slightly tilted wet substrate can pin on topographic defects, despite their lack of contact line. Instead, this pinning force has a gravito-capillary origin: liquid has to moves up or down and the interface has to deforms for the drop the pass the defect. I propose a semi-analytical model for arbitrary substrate topographies that matches the pinning force observed experimentally and numerically, without any fitting parameter. I finally demonstrate how to harness this pinning force to guide pendant drops on complex paths.
- Subjects :
- Physics - Fluid Dynamics
Subjects
Details
- Database :
- arXiv
- Journal :
- Phys. Rev. Fluids 9, L081601 (2024)
- Publication Type :
- Report
- Accession number :
- edsarx.2403.17584
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1103/PhysRevFluids.9.L081601