Hydrodynamic bearings support rotors in high-speed rotating systems by using a lubricating fluid to separate the rotating shaft from the stationary bearing surface, eliminating sliding friction and preventing wear. Their load-carrying capacity arises from a converging wedge that increases lubricant pressure, generating hydrodynamic forces to support the shaft. In journal bearings, cavitation occurs in the divergent wedge, where lubricant pressure drops to ambient levels, releasing gases dissolved in the lubricant. This work investigates the effects of mass conservation in hydrodynamic bearings on the dynamic behavior of a rigid rotor-bearing system, comparing a non-mass conserving model with the Ausas model, which overcomes numerical issues of the Elrod model in solving pressure and film fraction distributions. The influence of the cavitation model can be analyzed through rotor vibrations in the time and frequency domains, the motion orbit, and the lubricant fraction in the bearings. The proposed rotating system isolates bearing effects by considering only unbalance and weight to evaluate specifically the impact of the mass-conserving cavitation model on the performance of a rotor supported on a cylindrical bearing subject to cavitation.