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Main Authors: Diddens, Christian, Dekker, Pim J., Lohse, Detlef
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2402.17452
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author Diddens, Christian
Dekker, Pim J.
Lohse, Detlef
author_facet Diddens, Christian
Dekker, Pim J.
Lohse, Detlef
contents The evaporation of water/1,2-hexanediol binary drops shows remarkable segregation dynamics, with hexanediol-rich spots forming at the rim, thus breaking axisymmetry. While the segregation of hexanediol near the rim can be attributed to the preferential evaporation of water, the symmetry-breaking and spot formation could not yet be successfully explained. With three-dimensional simulations and azimuthal stability analysis of a minimal model, we investigate the flow and composition in the drop. We show that a slightly non-monotonic surface tension causes the emergence of a counter-rotating Marangoni vortex in the hexanediol-rich rim region, which subsequently becomes azimuthally unstable and forms the observed spots. Accurate measurements with several different methods reveal that the surface tension is indeed non-monotonic. This work provides valuable insight for applications like inkjet printing or spray cooling.
format Preprint
id arxiv_https___arxiv_org_abs_2402_17452
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Non-monotonic surface tension leads to spontaneous symmetry breaking in a binary evaporating drop
Diddens, Christian
Dekker, Pim J.
Lohse, Detlef
Fluid Dynamics
The evaporation of water/1,2-hexanediol binary drops shows remarkable segregation dynamics, with hexanediol-rich spots forming at the rim, thus breaking axisymmetry. While the segregation of hexanediol near the rim can be attributed to the preferential evaporation of water, the symmetry-breaking and spot formation could not yet be successfully explained. With three-dimensional simulations and azimuthal stability analysis of a minimal model, we investigate the flow and composition in the drop. We show that a slightly non-monotonic surface tension causes the emergence of a counter-rotating Marangoni vortex in the hexanediol-rich rim region, which subsequently becomes azimuthally unstable and forms the observed spots. Accurate measurements with several different methods reveal that the surface tension is indeed non-monotonic. This work provides valuable insight for applications like inkjet printing or spray cooling.
title Non-monotonic surface tension leads to spontaneous symmetry breaking in a binary evaporating drop
topic Fluid Dynamics
url https://arxiv.org/abs/2402.17452