Fig. 13 shows the friction coefficient as a function of the entrain- ment speed Uη and load W. Here, the prediction of the present fully nonlinear model is compared to that of the geometrically linear model. Quite surprisingly, the predicted friction coefficients are practically identical despite the differences in pressure and film thickness, see Fig. 11. Prediction of the regression equation (1) derived in [7] is also included in Fig. 13 and shows a very good agreement in the whole range of contact conditions.