Effects of surface roughness on shear viscosity

Michail Papanikolaou, Michael Frank, Dimitris Drikakis

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

This paper investigates the effect of surface roughness on fluid viscosity using molecular dynamics simulations. The three-dimensional model consists of liquid argon flowing between two solid walls whose surface roughness was modeled using fractal theory. In tandem with previously published experimental work, our results show that, while the viscosity in smooth channels remains constant across the channel width, in the presence of surface roughness it increases close to the walls. The increase of the boundary viscosity is further accentuated by an increase in the depth of surface roughness. We attribute this behavior to the increased momentum transfer at the boundary, a result of the irregular distribution of fluid particles near rough surfaces. Furthermore, although the viscosity in smooth channels has previously been shown to be independent of the strength of the solid-liquid interaction, here we show that in the presence of surface roughness, the boundary viscosity increases with the solid's wettability. The paper concludes with an analytical description of the viscosity as a function of the distance from the channel walls, the walls’ surface roughness, and the solid's wetting properties. The relation can potentially be used to adjust the fluid dynamics equations for a more accurate description of microfluidic systems.
LanguageEnglish
Article number033108
Number of pages7
JournalPhysical Review E
Volume95
Issue number3
DOIs
Publication statusPublished - 13 Mar 2017

Fingerprint

Shear Viscosity
Surface Roughness
Viscosity
surface roughness
viscosity
shear
Liquid
Wettability
Fluid
Rough Surface
fluids
Wetting
Microfluidics
three dimensional models
fluid dynamics
liquids
Fluid Dynamics
wettability
Dynamic Equation
Molecular Dynamics Simulation

Keywords

  • surface roughness
  • fluid viscosity
  • molecular dynamics simulation
  • fractal theory
  • smooth channels
  • wetting properties

Cite this

Papanikolaou, Michail ; Frank, Michael ; Drikakis, Dimitris. / Effects of surface roughness on shear viscosity. In: Physical Review E. 2017 ; Vol. 95, No. 3.
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Effects of surface roughness on shear viscosity. / Papanikolaou, Michail; Frank, Michael; Drikakis, Dimitris.

In: Physical Review E, Vol. 95, No. 3, 033108, 13.03.2017.

Research output: Contribution to journalArticle

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AB - This paper investigates the effect of surface roughness on fluid viscosity using molecular dynamics simulations. The three-dimensional model consists of liquid argon flowing between two solid walls whose surface roughness was modeled using fractal theory. In tandem with previously published experimental work, our results show that, while the viscosity in smooth channels remains constant across the channel width, in the presence of surface roughness it increases close to the walls. The increase of the boundary viscosity is further accentuated by an increase in the depth of surface roughness. We attribute this behavior to the increased momentum transfer at the boundary, a result of the irregular distribution of fluid particles near rough surfaces. Furthermore, although the viscosity in smooth channels has previously been shown to be independent of the strength of the solid-liquid interaction, here we show that in the presence of surface roughness, the boundary viscosity increases with the solid's wettability. The paper concludes with an analytical description of the viscosity as a function of the distance from the channel walls, the walls’ surface roughness, and the solid's wetting properties. The relation can potentially be used to adjust the fluid dynamics equations for a more accurate description of microfluidic systems.

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