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Photo Marie Skepö

Marie Skepö

Professor

Photo Marie Skepö

Effect of patchwise slip on fluid flow

Author

  • Maria Pihl
  • Bengt Jönsson
  • Marie Skepö

Summary, in English

In this paper, we show that large connected slip patches (hydrophobic patches) are a necessity to induce macroscopic slip effects of water flow in microchannels. For this purpose, the 2D fluid flow between a planar stationary surface with alternating stick and slip patches and a parallel planar surface moving with a constant relative velocity has been studied by computer simulations based on Navier-Stokes equations. A slip patch is defined as the slipping length in a 2D system or a slip area of the surface in a 3D system. The simulations reveal that the ratio (size of each slip patch)/(distance between the two parallel interfaces) has profound effect on the viscous stress on the moving surface when this ratio is around and above one. However, when the ratio is much below one, the effect of the slip patches are minor, even if the area fraction of slip patches are higher than 50 %. Obviously, the stick patches adjacent to the slip patches act as effective barriers, preventing the fluid velocity to increase near the surface with alternating stick and slip patches. The obtained results are scalable and applicable on all length scales, with an exception for narrow channels in the subnano regime, i.e. < 1 nm where specific effects as the atomistic composition and the nanostructure of the wall as well as the interactions between the wall and the water molecules have an effect.

Department/s

  • Biophysical Chemistry
  • Computational Chemistry
  • eSSENCE: The e-Science Collaboration

Publishing year

2014

Language

English

Pages

341-347

Publication/Series

Microfluidics and Nanofluidics

Volume

17

Issue

2

Document type

Journal article

Publisher

Springer

Topic

  • Theoretical Chemistry (including Computational Chemistry)
  • Physical Chemistry (including Surface- and Colloid Chemistry)

Keywords

  • Slip patch
  • Stick
  • COMSOL Multiphysics
  • Navier-Stokes equations

Status

Published

ISBN/ISSN/Other

  • ISSN: 1613-4982