ABSTRACT
For hydrodynamic lubrication, the viscosity, m, is the most important characteristic of a fluid lubricant because it has a major role in the formation of a fluid film.
However, for boundary lubrication the lubricity characteristic is important. The
viscosity is a measure of the fluid’s resistance to flow. For example, a low-
viscosity fluid flows faster through a capillary tube than a fluid of higher
viscosity. High-viscosity fluids are thicker, in the sense that they have higher
internal friction to the movement of fluid particles relative to one another.