The Influence of Fluid Inertia in Steady Laminar Lubrication

Abstract

In this work the authors give a method to determine the influence of the inertial terms, in the case of a lubricated slider bearing, based on the solution of the “inverse problem.” That is to determine the geometry of a slider bearing given the pressure distribution, the lubricant flow rate and the slider velocity. Unlike other methods till now proposed (i.e., the Slezkin and Targ, Kahlert, Constantinescu methods), in this work no simplifying assumptions have been made. A sensible influence of the inertial forces, already at the value of the modified Reynolds number Re* = 0.1, has been shown. At the same load capacity, the minimum thickness of the film decreases because of the inertia (at values of the parameters Re* = 0.1 and a = 0.2 the decreasing is about five percent). At a given geometry of the lubricant film, the inertial forces increase the load capacity, the friction forces and the friction coefficient if they are compared with the linear case. A comparison between the results of the present study and the results obtained solving the “direct problem” with approximate methods shows a good agreement relating to quality.