In vertically oriented machines with tilting-pad journal bearings, there is no static load that allow tocalculate the bearing properties around a determined static position. As a result, most of simulationsare performed by solving Reynolds equation at each time-step which can result in long computationaltime. To avoid this concern, a simplified model is used that takes in account the variation of unbalanceload depending on the pad configuration. This nonlinear model is used to simulate the dynamics ofa hydropower turbine and compared with the Campbell diagram calculations used from hydropowerindustry standards. A comparison between the linear and nonlinear model is performed to evaluate howaccurate the linear model is and until which limits it can be relevant. In case of qualitative discrepancies inthe results in terms of natural frequencies and damping ratios, an improvement of the Campbell diagramcalculation is proposed to obtain a more accurate linear model.