Publication Date
7-25-2023
Document Type
Article
Publication Title
Proceedings of the National Academy of Sciences of the United States of America
Volume
120
Issue
30
DOI
10.1073/pnas.2306088120
Abstract
The Rayleigh–Plateau instability occurs when surface tension makes a fluid column become unstable to small perturbations. At nanometer scales, thermal fluctuations are comparable to interfacial energy densities. Consequently, at these scales, thermal fluctuations play a significant role in the dynamics of the instability. These microscopic effects have previously been investigated numerically using particle-based simulations, such as molecular dynamics (MD), and stochastic partial differential equation–based hydrodynamic models, such as stochastic lubrication theory. In this paper, we present an incompressible fluctuating hydrodynamics model with a diffuse-interface formulation for binary fluid mixtures designed for the study of stochastic interfacial phenomena. An efficient numerical algorithm is outlined and validated in numerical simulations of stable equilibrium interfaces. We present results from simulations of the Rayleigh–Plateau instability for long cylinders pinching into droplets for Ohnesorge numbers of Oh = 0.5 and 5.0. Both stochastic and perturbed deterministic simulations are analyzed and ensemble results show significant differences in the temporal evolution of the minimum radius near pinching. Short cylinders, with lengths less than their circumference, were also investigated. As previously observed in MD simulations, we find that thermal fluctuations cause these to pinch in cases where a perturbed cylinder would be stable deterministically. Finally, we show that the fluctuating hydrodynamics model can be applied to study a broader range of surface tension–driven phenomena.
Funding Number
DE-SC0022158
Funding Sponsor
U.S. Department of Energy
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Department
Physics and Astronomy
Recommended Citation
Bryn Barker, John B. Bell, and Alejandro L. Garcia. "Fluctuating hydrodynamics and the Rayleigh–Plateau instability" Proceedings of the National Academy of Sciences of the United States of America (2023). https://doi.org/10.1073/pnas.2306088120
