Surface roughness effects for newtonian and non-newtonian lubricants

Abstract

In the present study, a numerical solution is presented to investigate the combined effects of lubricant rheology and surface roughness parameters on the characteristic of elastohydrodynamic lubrication problem for point contact. Sinusoidal waviness for surface roughness is considered to show the effect of changing amplitude and wavelength on the film thickness and pressure profile. The results show that, surface waviness leads to random fluctuations of pressure and film thickness for both modes of lubricant of Newtonian and non-Newtonian. As the amplitude of the waviness increase, the more fluctuations of pressure profile and film profile occur. Changing the wavelength of wavy surface shows that the amplitude of the pressure fluctuation becomes a little more remarkable as wavelength increase. The difference between Newtonian and non-Newtonian lubricant is that the non-parallel film shape in the contact region occurs for non-Newtonian model in addition to the reduction in film thickness compared to the Newtonian model.