Effective mean free path and viscosity of confined gases

Jianfei Xie, Matthew K. Borg, Livio Gibelli, Oliver Henrich, Duncan A. Lockerby, Jason M. Reese

Research output: Contribution to journalArticle

1 Citation (Scopus)

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.
LanguageEnglish
Article number072002
Number of pages10
JournalPhysics of Fluids
Volume31
Issue number7
DOIs
Publication statusPublished - 16 Jul 2019

Fingerprint

mean free path
viscosity
gases
simulation
shear stress
strain rate
Monte Carlo method
molecules
molecular dynamics
collisions
geometry
predictions
atoms
interactions

Keywords

  • molecular mean free path (MFP)
  • Monte Carlo method
  • molecular dynamics simulations
  • intermolecular interactions
  • collision

Cite this

Xie, J., Borg, M. K., Gibelli, L., Henrich, O., Lockerby, D. A., & Reese, J. M. (2019). Effective mean free path and viscosity of confined gases. Physics of Fluids, 31(7), [072002]. https://doi.org/10.1063/1.5108627
Xie, Jianfei ; Borg, Matthew K. ; Gibelli, Livio ; Henrich, Oliver ; Lockerby, Duncan A. ; Reese, Jason M. / Effective mean free path and viscosity of confined gases. In: Physics of Fluids. 2019 ; Vol. 31, No. 7.
@article{9a927841d63e4bfe810094bd087f10ce,
title = "Effective mean free path and viscosity of confined gases",
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.",
keywords = "molecular mean free path (MFP), Monte Carlo method, molecular dynamics simulations, intermolecular interactions, collision",
author = "Jianfei Xie and Borg, {Matthew K.} and Livio Gibelli and Oliver Henrich and Lockerby, {Duncan A.} and Reese, {Jason M.}",
year = "2019",
month = "7",
day = "16",
doi = "10.1063/1.5108627",
language = "English",
volume = "31",
journal = "Physics of Fluids",
issn = "1070-6631",
number = "7",

}

Xie, J, Borg, MK, Gibelli, L, Henrich, O, Lockerby, DA & Reese, JM 2019, 'Effective mean free path and viscosity of confined gases' Physics of Fluids, vol. 31, no. 7, 072002. https://doi.org/10.1063/1.5108627

Effective mean free path and viscosity of confined gases. / Xie, Jianfei; Borg, Matthew K.; Gibelli, Livio; Henrich, Oliver; Lockerby, Duncan A.; Reese, Jason M.

In: Physics of Fluids, Vol. 31, No. 7, 072002, 16.07.2019.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Effective mean free path and viscosity of confined gases

AU - Xie, Jianfei

AU - Borg, Matthew K.

AU - Gibelli, Livio

AU - Henrich, Oliver

AU - Lockerby, Duncan A.

AU - Reese, Jason M.

PY - 2019/7/16

Y1 - 2019/7/16

N2 - 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.

AB - 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.

KW - molecular mean free path (MFP)

KW - Monte Carlo method

KW - molecular dynamics simulations

KW - intermolecular interactions

KW - collision

UR - https://aip.scitation.org/journal/phf

U2 - 10.1063/1.5108627

DO - 10.1063/1.5108627

M3 - Article

VL - 31

JO - Physics of Fluids

T2 - Physics of Fluids

JF - Physics of Fluids

SN - 1070-6631

IS - 7

M1 - 072002

ER -

Xie J, Borg MK, Gibelli L, Henrich O, Lockerby DA, Reese JM. Effective mean free path and viscosity of confined gases. Physics of Fluids. 2019 Jul 16;31(7). 072002. https://doi.org/10.1063/1.5108627