Exploring turbulence and elastic deformation: Novel insights into dynamic instability in water-lubricated composite journal bearings for hub-type rim-driven thrusters

This study investigated the performance of a hub-type composite journal bearing system in both steady and dynamic states by simplifying the system into a balanced rotor bearing system. By considering turbulence and bearing liner deformation, we identified, for the first time, the onset of expansion of the dynamically unstable region. Additionally, we propose a recommended operating region restricted by the optimum boundary for the maximum load-carrying capacity while ensuring system stability. At a Reynolds number of 5000, we determined the optimal conditions for achieving both the maximum load-carrying capacity and system stability. Finally, we demonstrate that optimal performance can be achieved not only through adjustments in the operating conditions, but also through the selection of composite bearing materials.