Shear Viscosity and Self-Diffusion in Water

An analysis is performed of two important transport processes in a liquid water: kinematic shear viscosity and self-diffusion. The approach to shear viscosity is based on considering the effects of friction between two neighboring molecular layers displaced relative to each other. The pattern of shear viscosity in water is then identical to the one in argon. The contribution from molecular motion and pulse from one layer to another is negligible. The behavior of the kinematic shear viscosity of water is studied in detail for two characteristic situations: on the curve of liquid-vapor coexistence and isotherms. As in argon, self-diffusion in water is assumed to be associated with two main factors: the transfer of molecules by nanoscopic vortex hydrodynamic modes and their collective agitation on molecular scales. The latter mechanism is adequately described by Einstein's formula at a fixed molecular radius determined by analyzing the shear viscosity of water.