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Updated: Sep 11, 2025

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Exact nonlocal hydrodynamics predict rarefaction effects
Florian Kogelbauer1, Ilya Karlin1
1ETH Zurich, Department of Mechanical and Process Engineering, 8092 Zurich, Switzerland.
Abstract:
We combine the theory of slow spectral closure for linearized Boltzmann equations with Maxwell's kinetic boundary conditions to derive optimal hydrodynamics with arbitrary accommodation. Focusing on shear-mode dynamics, we obtain explicit steady state solutions in terms of Fourier integrals and closed-form expressions for the mean flow and the stress. We demonstrate that the exact nonlocal fluid model correctly predicts several rarefaction effects with accommodation, including the Couette flow and thermal creep in a plane channel.
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