Hydrodynamic bearings and aerodynamic bearings are components which ensure the guiding of rotating machines, such as turbines and reactors. This equipment operates under very severe operating conditions, with a high rotational speed and high radial load. In order to improve the hydrodynamic performance of these rotating machines, manufacturers specializing in the manufacture of hydrodynamic plain bearings have designed a bearing model with its textured interior surface. This book provides a numerical analysis carried out to observe the effect of a turbulent fluid flow in a non-textured and textured plain bearing and to see the improvement in hydrodynamic and tribological performance on both un-textured and textured surfaces of plain bearings, under severe operating parameters. It also presents an analysis of the structural behavior of a hydrodynamic and aerodynamic bearing with a non-textured and textured surface.