Stability of submerged four-lobe oil journal bearings under dynamic load

A non-linear transient method was used to predict the journal centre trajectory for a submerged four-lobe oil journal bearing under (1) unidirectional constant load, (2) unidirectional periodic load, and (3) variable rotating load. The Reynolds equation was integrated using the Jakobsson-Floberg-Olsson cavitation zone model, and oil film prehistory effects were taken into account. The journal centre trajectories obtained were compared with those obtained for submerged plain cylindrical bearings under similar loading conditions. It was observed that the excursions of the journal centre were subdued, unlike for the plain cylindrical bearings, where the journal centre had a large excursion before it became stable or ended in a limit cycle. Interesting trajectories were observed for the periodic load. A three-dimensional plot of the pressure distribution in the bearing clearance was obtained using computer graphics.