Spherical and sessile droplet dynamics by fluctuating hydrodynamics

Publication Date

1-1-2025

Document Type

Article

Publication Title

Physics of Fluids

Volume

37

Issue

1

DOI

10.1063/5.0249847

Abstract

We simulate the mesoscopic dynamics of droplets formed by phase-separated fluids at nanometer scales where thermal fluctuations are significant. Both spherical droplets fully immersed in a second fluid and sessile droplets which are also in contact with a solid surface are studied. Our model combines a Cahn-Hilliard formulation with incompressible fluctuating hydrodynamics; for sessile droplets, the fluid-solid contact angle is specified as a boundary condition. Deterministic simulations with an applied body force are used to measure the droplets' mobility from which a diffusion coefficient is obtained using the Einstein relation. Stochastic simulations are independently used to obtain a diffusion coefficient from a linear fit of the variance of a droplet's position with time. In some scenarios, these two measurements give the same value but not in the case of a spherical droplet initialized near a slip wall or in the case of sessile droplets with large contact angles ( ≥ 90 ° ) on both slip and no-slip surfaces.

Comments

The final version of the article will be available in February 2026 due to embargo policy

Department

Physics and Astronomy

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