Using numerical simulations, the effect of surface roughness on elastohydrodynamic lubrication (EHL) under simple sliding point contacts is investigated. Transverse roughness is on the stationary surface. Four fluid flow models, i.e. thermal Newtonian, isothermal Newtonian, thermal Eyring, and isothermal Eyring models, are employed in the analyses. The effects of temperature rise, lubricant rheology, and amplitude and wavelength of asperities on micro-EHL films are elucidated. Behaviours of oil films with short wavelength of asperities are found to be complex. The deformations of asperities are also compared under the four fluid flow models.

Numerical analyses based on Newtonian and Eyring fluid models are carried out to simulate the effects of inlet oil starvation in thermal elastohydrodynamic lubrication (TEHL) point contacts. It is assumed that the surface with transverse roughness is stationary and smooth surface is moving. Results of smooth TEHL contacts based on Newtonian fluid model are also presented as a reference. It is found that the temperature in the oil film increases suddenly at the inlet meniscus like the pressure build-up because of the discontinuous oil film at that boundary. The increasing degree of the inlet starvation raises the average temperature in the oil film for both smooth and rough contacts. The Newtonian maximum pressure and temperature for the rough contact occur at the macroscopic horseshoe-shaped constriction. Those of the Eyring fluid model still locate at the contact centre. As the degree of oil starvation increases, the differences in the pressure and film thickness distributions in rough elastohydrodynamic lubrication contacts between the Newtonian and Eyring fluid flow models decrease.