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Molecular kinetic modelling of nanoscale confined flows

Published online by Cambridge University Press:  05 June 2025

Baochao Shan ,
Manuel Torrilhon ,
Zhaoli Guo  and
Yonghao Zhang Open the ORCID record for Yonghao Zhang [Opens in a new window]
Baochao Shan
Affiliation:
Applied and Computational Mathematics, RWTH Aachen University, Aachen 52062, Germany
Manuel Torrilhon*
Affiliation:
Applied and Computational Mathematics, RWTH Aachen University, Aachen 52062, Germany
Zhaoli Guo*
Affiliation:
Institute of Interdisciplinary Research for Mathematics and Applied Science, Huazhong University of Science and Technology, Wuhan 430074, PR China
Yonghao Zhang*
Affiliation:
Centre for Interdisciplinary Research in Fluids, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, PR China School of Engineering Science, University of Chinese Academy of Sciences, Beijing 101408, PR China
*
Corresponding authors: Yonghao Zhang, yonghao.zhang@imech.ac.cn; Manuel Torrilhon, mt@acom.rwth-aachen.de; Zhaoli Guo, zlguo@hust.edu.cn
Corresponding authors: Yonghao Zhang, yonghao.zhang@imech.ac.cn; Manuel Torrilhon, mt@acom.rwth-aachen.de; Zhaoli Guo, zlguo@hust.edu.cn
Corresponding authors: Yonghao Zhang, yonghao.zhang@imech.ac.cn; Manuel Torrilhon, mt@acom.rwth-aachen.de; Zhaoli Guo, zlguo@hust.edu.cn
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Abstract

We have established a novel molecular kinetic model that addresses fundamental challenges in the non-equilibrium transport of nanoscale confined fluids, such as rarefaction and fluid inhomogeneities, which are crucial to a range of scientific and engineering fields. The proposed model explicitly considers fluid–solid molecular interactions in the transport equations, eliminating the reliance on predefined boundary conditions. By consistently accounting for molecular interactions between fluids and solids, the unified model captures both intrinsic and apparent non-hydrodynamic effects, as well as real fluid behaviours. Rigorous comparisons with molecular dynamics simulations demonstrate that the present model accurately predicts unique features of strongly inhomogeneous fluid flows, including fluid adsorption, solvation force, velocity slip and temperature jump. Therefore, this mesoscopic model bridges the gap between molecular-scale dynamics and macroscopic hydrodynamics, enabling a practical simulation tool for nanoscale surface-confined flows. Moreover, it offers valuable insights into the molecular mechanisms underlying anomalous transport phenomena observed in confined flows, such as the disappearance and re-emergence of the Knudsen minimum.

JFM classification

Micro-/Nano-fluid dynamics: Micro-/Nano-fluid dynamics Rarefied Gas Flow: Kinetic theory
Type
JFM Papers
Information
Journal of Fluid Mechanics , Volume 1012 , 10 June 2025 , A20
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© The Author(s), 2025. Published by Cambridge University Press

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