The Stribeck curve shows the friction coefficient as a function of speed, viscosity and load. The viscosity times speed over load parameter can be interpreted as a film thickness. The film thickness over roughness parameter unifies friction curves in the isoviscous rigid regime. In this paper, the Stribeck curve is predicted numerically in the full-film Elastohydrodynamic Lubrication regime. It is shown that the lambda ratio is not the most appropriate parameter. A more elaborate parameter including the operating conditions and based on the Amplitude Reduction Theory  gives much better results. For a complex surface topography, the full numerical simulation is time-consuming. A rapid prediction method is proposed. Good agreement is found between the full numerical simulation and the prediction.
Zhang, Y., Biboulet, N., Venner, C. H., & Lubrecht, A. A. (2019). Prediction of the Stribeck curve under full-film Elastohydrodynamic Lubrication. Tribology international. https://doi.org/10.1016/j.triboint.2019.01.028