Article

International Journal of Thermophysics

, Volume 4, Issue 2, pp 97-114

Pressure tensor and viscosity coefficients of a soft sphere liquid under shear

  • S. HessAffiliated withChemical Engineering Science Division, National Bureau of Standards
  • , H. J. M. HanleyAffiliated withChemical Engineering Science Division, National Bureau of Standards

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Abstract

General properties and consequences of the distortion of the structure of a simple liquid subjected to a planar shear flow are reported. In particular, the orientational distribution of particles in the first coordination shell around a given particle is analyzed, and the effect of this distribution on the pressure tensor is discussed. The distorted distribution gives rise to a set of non-Newtonian viscosity coefficients reflecting the occurrence of normal pressure differences in the liquid. Numerical values of these viscosities are given for a soft sphere fluid at 7/8 of the freezing density using the technique of nonequilibrium molecular dynamics. A wide range of shear rates is considered and all viscosity coefficients are found to be functions of the shear rate.

Key words

nonequilibrium molecular dynamics non-Newtonian effects radial distribution function Theological behavior viscosity