Gravito-capillary pinning of pendant droplets under wet uneven surfaces
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arXiv
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| Format: | Preprint |
| Published: |
2024
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| _version_ | 1866909281277706240 |
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| author | Jambon-Puillet, Etienne |
| author_facet | Jambon-Puillet, Etienne |
| contents | 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. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2403_17584 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Gravito-capillary pinning of pendant droplets under wet uneven surfaces Jambon-Puillet, Etienne Fluid Dynamics 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. |
| title | Gravito-capillary pinning of pendant droplets under wet uneven surfaces |
| topic | Fluid Dynamics |
| url | https://arxiv.org/abs/2403.17584 |