2D numerical simulation of tear film dynamics: Effects of shear-thinning properties

Hamza Mehdaoui, Hamid Ait Abderrahmane, Faïçal Nait Bouda, Aimad Koulali, Sofiane Hamani

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

The influence of the shear-thinning properties on tear dynamics is analyzed using 2D numerical simulations. The simulations were conducted in conditions close to those of the actual tear film dynamics. The paper deals with the spreading of the shear-thinning tear film on a spherical cornea with blinking. The shear-thinning properties are described using Cross's rheological model, known as the model that describes well shear-thinning properties of actual tears. We solved the continuity and the momentum equations using the mono-fluid formulation and the volume of fluid (VOF) method. We have examined the influence of rheological properties namely, the time constant, the zero shear viscosity, and the flow behavior index on the tear film profile. The results confirm that the curvature delays the risk of film rupture. The results also indicate that the values of the shear-thinning parameters within the range of the values measured in-vivo are the ones that delay tear-film breakup. These values provide quasi-uniform thin tear film and ensure a low wall shear stress lubrication between the moving eyelid and the cornea surface. The suggested values for the shear-thinning parameters can serve as a starting point for designing efficient artificial tears to alleviate moderate symptoms of dry eye syndrome.

Original languageBritish English
Pages (from-to)128-136
Number of pages9
JournalEuropean Journal of Mechanics, B/Fluids
Volume90
DOIs
StatePublished - 1 Nov 2021

Keywords

  • CFD
  • Curved substrate
  • Dry eye syndrome
  • Shear-thinning fluid
  • Tear film
  • Tear film breakup

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