Effective mean free path and viscosity of confined gases

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Xie, Jianfei and Borg, Matthew K. and Gibelli, Livio and Henrich, Oliver and Lockerby, Duncan A. and Reese, Jason M. (2019) Effective mean free path and viscosity of confined gases. Physics of Fluids, 31 (7). 072002. ISSN 1089-7666 (https://doi.org/10.1063/1.5108627)

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Abstract

The molecular mean free path (MFP) of gases in confined geometries is numerically evaluated by means of the direct simulation Monte Carlo method and molecular dynamics simulations. Our results show that if calculations take into account not only intermolecular interactions between gas molecules but also collisions between gas molecules and wall atoms, then a space-dependent MFP is obtained. The latter, in turn, permits one to define an effective viscosity of confined gases that also varies spatially. Both the gas MFP and viscosity variation in surface-confined systems have been questioned in the past. In this work, we demonstrate that this effective viscosity derived from our MFP calculations is consistent with those deduced from the linear-response relationship between the shear stress and strain rate using independent nonequilibrium Couette-style simulations as well as the equilibrium Green-Kubo predictions.

ORCID iDs

Xie, Jianfei, Borg, Matthew K., Gibelli, Livio, Henrich, Oliver ORCID logoORCID: https://orcid.org/0000-0003-0384-982X, Lockerby, Duncan A. and Reese, Jason M.;
  • Item type:Article
    ID code:68893
    Dates:
    Date
    Event
    16 July 2019
    Published
    17 June 2019
    Accepted
    Subjects:Science > Physics
    Department:Faculty of Science > Physics
    Depositing user: Pure Administrator
    Date deposited:17 Jul 2019 13:53
    Last modified:21 Dec 2024 01:19
    Related URLs:
    URI:https://strathprints.strath.ac.uk/id/eprint/68893
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