Nanoscale sheared droplet: volume-of-fluid, phase-field and no-slip molecular dynamicsShow others and affiliations
2022 (English)In: Journal of Fluid Mechanics, ISSN 0022-1120, E-ISSN 1469-7645, Vol. 940, article id A10Article in journal (Refereed) Published
Abstract [en]
The motion of the three-phase contact line between two immiscible fluids and a solid surface arises in a variety of wetting phenomena and technological applications. One challenge in continuum theory is the effective representation of molecular motion close to the contact line. Here, we characterize the molecular processes of the moving contact line to assess the accuracy of two different continuum two-phase models. Specifically, molecular dynamics simulations of a two-dimensional droplet between two moving plates are used to create reference data for different capillary numbers and contact angles. We use a simple-point-charge/extended water model. This model provides a very small slip and a more realistic representation of the molecular physics than Lennard-Jones models. The Cahn-Hilliard phase-field model and the volume-of-fluid model are calibrated against the drop displacement from molecular dynamics reference data. It is shown that the calibrated continuum models can accurately capture droplet displacement and droplet break-up for different capillary numbers and contact angles. However, we also observe differences between continuum and atomistic simulations in describing the transient and unsteady droplet behaviour, in particular, close to dynamical wetting transitions. The molecular dynamics of the sheared droplet provide insight into the line friction experienced by the advancing and receding contact lines. The presented results will serve as a stepping stone towards developing accurate continuum models for nanoscale hydrodynamics.
Place, publisher, year, edition, pages
Cambridge University Press, 2022. Vol. 940, article id A10
Keywords [en]
breakup/coalescence, contact lines, microscale transport
National Category
Physical Chemistry Nano Technology Fluid Mechanics and Acoustics
Identifiers
URN: urn:nbn:se:sh:diva-48791DOI: 10.1017/jfm.2022.219ISI: 000778572600001Scopus ID: 2-s2.0-85129201165OAI: oai:DiVA.org:sh-48791DiVA, id: diva2:1653138
Funder
Swedish Research CouncilEU, European Research Council, 1.1.1.1/20/A/070Swedish Research Council, VR-2014-56802022-04-212022-04-212022-05-19Bibliographically approved