Abstract: Interferometric experiments are carried out to study the profile of an elastohydrodynamic lubricating film, which is generated by polybutene lubricants of high viscosities under pure sliding at ultra-slow speeds, and an obvious inlet dimple is observed. The experimental results demonstrate that the depth of the dimple increases with increasing loads, and increases with entrainment speeds until a maximum is reached. Moreover, in the experiments it is easier to generate the inlet dimple when lubricants of higher viscosity are used. Under conditions of pure sliding, the dependence of film thickness on loads and speeds deviates largely from the classical theory. The present experiments provides a validation of previous numerical elastohydrodynamic lubrication analysis with inlet dimples.

Key words: Elastohydrodynamic lubrication, Inlet dimple, Limiting shear stress, Wall slippage