Contributed by the Applied Mechanics Division of THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS for publication in the ASME JOURNAL OF APPLIED MECHANICS. Manuscript received by the ASME Applied Mechanics Division, August 16, 2000; final revision, April 28, 2001. Associated Editor: D. A. Siginer.
In recent years, hydrodynamically lubricated bearings are used under increasingly severe conditions of high speed and heavy load. Owing to the friction, the temperature of the lubricating film rises under such operations and the viscosity of the lubricating oil decreases. Lubricating oils often contain sufficient additives of high molecular-weight polymers as a viscosity index improver in order to prevent viscosity variation with temperature change. Experimental evidence of rheological characteristics of polymer-thickened oils indicates that such lubricants behave as non-Newtonian viscous fluids such as pseudo-plastic fluids when the amount of additives is small. It has been confirmed that the non-Newtonian viscous behavior of polymer-thickened oils may be...
