Origins of Pressure and Viscosity Oscillation With Film Thickness in Ultra Thin Lubricating Films

Both pressure and viscosity have been observed via molecular simulation to oscillate with film thickness in ultra thin lubricating films. This oscillation may need to be considered in lubricated system design for applications that operate in the thin film lubrication regime. Oscillatory behavior occurs when the thickness of the lubricant is on the same order of magnitude as the fluid molecules themselves. It has been suggested by many researchers that this oscillation is related to the layering that occurs in confined fluids. In the present work, this relationship between molecular configuration and oscillation in fluid properties is further investigated. A quantifiable relationship is identified which may enable prediction of oscillatory effects based on fluid atom size and wall separation.