5. Friction model

This new theory for modeling fluid viscosity is based on friction concepts from classical mechanics and Van der Waals theory. It differs from previous theories in that the viscosity of dense fluids, which characterizes pure shear flow, is approached as a mechanical property, and not as a transport property. Viscosity is separated into a dilute gas term and a friction term, which are related to the attractive and repulsive Van der Waals pressure terms. As a result, a simple cubic equation of state well suited to an accurate representation of the pressure-temperature relationship is sufficient to model fluid viscosity over a wide range of pressures.