Stability and Instability of a Two-Mode Rotor Supported by Two Fluid-Lubricated Bearings

[+] Author and Article Information
A. Muszynska, J. W. Grant

Bently Rotor Dynamics Research Corporation, Minden, NV 89423-2529

J. Vib. Acoust 113(3), 316-324 (Jul 01, 1991) (9 pages) doi:10.1115/1.2930187 History: Received April 01, 1990; Online June 17, 2008


This paper is a continuation of the series of papers on application of the improved fluid force model for lightly loaded shafts rotating in a fluid environment. The fluid force model is based on the strength of the circumferential flow. The considered two-mode rotor is supported in two fluid-lubricated bearings, thus it contains two potential sources of instability. The eigenvalue solution predicts thresholds of stability and provide natural frequencies and modes of the system, including the flow-induced mode. The nonlinear model of the rotor/bearing system allows for evaluation of parameters of after instability onset self-excited vibrations (whirl and whip). Experimental data illustrate the dynamic phenomena predicted by the model. In particular, they show an undocumented new phenomenon, the simultaneous existence of two whip vibrations with frequencies corresponding to two modes of the rotor. A radial preload of the rotor results in journal eccentric position inside the bearings, which causes specific changes in the fluid forces (an increase of radial stiffness and reduction of circumferential velocity) providing better stability of the rotor. This effect is illustrated by the experimental data, as well as is predicted by the model.

Copyright © 1991 by The American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.






Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In