Influence of Surface Geometry on the Hydrodynamic Performances of Parallel Bearings in Transient Flow Conditions

Because a perfectly smooth surface does not actually exist, the classical principles of fluid mechanics dictate that the flow between two surfaces that are in relative motion is fundamentally unsteady. Therefore, the fluid film profile can be submitted to rapid oscillations in both space and time. This article shows how these oscillations become dependent on the surface geometry. By employing a transient mass-conserving cavitation model, we study several cases in which surface roughness and surface texturing are considered on both surfaces of a parallel bearing. For an applied load, the model shows the impact of surface geometry on the hydrodynamic performance of the bearing in terms of nominal film thickness, friction force, and volumetric flow rate. In addition, the results illustrate how different operating parameters such as the applied load and the speed of the moving surface affect the presence of cavitation within the bearing.