2025-11-18 パシフィック・ノースウェスト国立研究所 (PNNL)
This study establishes an unambiguous theoretical analysis for modeling fluid flow in confined channels that defines two regions, one where nanoscale interfacial dynamics are critical and another where the flow is accurately modeled by standard continuum theory.(Image by Haoyuan Shi and Jaehun Chun | Pacific Northwest National Laboratory)
＜関連情報＞
- https://www.pnnl.gov/publications/articulating-breakdown-continuum-descriptions-nanoconfined-fluid-flows
- https://pubs.aip.org/aip/jcp/article/163/13/134708/3366794/Incorporating-the-molecular-scale-into-a
閉じ込められた水系の流体力学的記述に分子スケールを組み込む
Incorporating the molecular-scale into a hydrodynamic description of confined aqueous systems
Haoyuan Shi;Christopher J. Mundy;Gregory K. Schenter;Jaehun Chun
The Journal of Chemical Physics Published:October 07 2025
DOI:https://doi.org/10.1063/5.0279626
Hydrodynamics provides a continuum-level description of fluid motion, but its applicability at the nanoscale becomes uncertain due to the emerging importance of molecular-level effects such as spatial heterogeneity. Hydrodynamic boundary conditions that incorporate molecular details allow us to partition the system into a near-wall region and a bulk fluid region. We identify a hydrodynamic wall located inside the fluid that determines where slip begins. By extending the hydrodynamic wall with the slip length, the position of the extrapolated wall is established. This offers a unified description of both slip and stagnant flow behaviors, with wall hydrophobicity characterized by the relative location of the extrapolated wall with respect to the physical wall. Employing this concept in analyses of equilibrium molecular dynamics (MD) and non-equilibrium MD simulations of Couette and Poiseuille flows, our results demonstrate consistency between equilibrium and non-equilibrium approaches across different flow types and confinement levels. This demonstrates the robust nature of linear response theory. We then explore the effects of fluid-wall and bulk fluid interactions on the hydrodynamic properties. These findings enhance the effectiveness of molecular-based simulations for investigating complex confined systems in nanofluidics, biology, and colloidal science, offering a complementary molecular-scale perspective to traditional continuum approaches.
