Influence of the Fluid Inertia Forces on the Dynamic Characteristics of Externally Pressurized Thrust Bearings : 2nd Report, Evaluation of Various Approximate Solutions for the Influence of Film Inertia Forces on the Dynamic Performance of Externally Pressurized Infinitely Long Thrust Bearings

摘要

Based on the Navier-Strokes equations in which the pressure is assumed to be constant across the film thickness, various approximate solutions and an exact one for the dynamic performance of externally pressurized infinitely long thrust bearings in a laminar flow regime are presented under the assumption of a small harmonic vibration. From comparison of the approximate solutions with the exact one, it is concluded that some kind of averaging approach in which a part of the time dependent term is treated exactly while the other inertia terms are averaged out across the film thickness gives close approximations in a wide range of designing conditions, and that the other kind of averaging approach in which all the inertia terms including the time dependent term are averaged out across the film thickness gives fairly good approximations.