The shear viscosity of a hard-sphere fluid via nonequilibrium molecular dynamics

The calculations of shear viscosity were performed for the four cases of the particle number N=108, 256, 500, and 1372. The periodic boundary condition has been generalized to the system in which the stationary Couette flow is present. The viscosity was calculated from the temporal increase in the temperature due to dissipation as well as from the pressure tensor. The values of the viscosity were obtained at the different shear rates over the entire fluid density range. The calculated values are rather in good agreement with the Alder–Gass–Wainwright results. A general tendency of the shear viscosity to decrease with shear rate is observed. The decrease in the viscosity with N due to the size effect was observed at freezing density. The Stokes relation was dealt with, and the approximate nonspherical pair distribution functions in the presence of Couette flow were calculated.