The predictions of the regression equation (1) are included in Fig. 2. The agreement between the theoretical predictions and the experimental values corresponding to the hydrodynamic lubrica- tion regime is reasonably good with the highest discrepancy reaching 30% at the lowest load. At the same time, the dependence
of the friction coefficient on Uη (i.e., the slope on the log–log plot)
and the dependence on the load are in a good agreement.