It can be seen that the results corresponding to each load form a part of the classical Stribeck curve with a continuous transition between the results corresponding to the lubricants of different
viscosity. At high values of Uη, the dependence of the friction
coefficient on Uη appears approximately linear on the log–log plot which indicates that the contact operates in the hydrodynamic
lubrication regime. At low values of Uη, the contact operates in the mixed lubrication regime and the friction coefficient increases
with decreasing Uη.