Self Excited Oscillations in Journal Bearings

Abstract

Under certain rotation rates, a rotor, supported by an oil-lubricated journal bearing, can experience excessive shaft vibration. Two types of oscillations can exist called oil whirl and oil whip. Oil whirl produces a circular orbit in a direction of the same sense as the shaft rotation but at a value of about 45% of the shaft rotation speed. Oil whip is a more violent oscillations which occurs at the resonance frequency of the shaft system. Both of these oscillation are predicted in this report by obtaining an analytic description of the fluid forces and inserting these into the dynamic equations for the rotor system. Oil whirl is shown to be an auto rotation, omega, of the journal centroid at a rate of one half of the shaft rotational speed. Oil whip is shown to occur when the frequency of autorotation exceeds the natural frequency of the shaft system.

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Document Details

Document Type
Technical Report
Publication Date
Mar 12, 1983
Accession Number
ADA130200

Entities

People

  • Wilbur L. Hankey

Organizations

  • Wright Laboratory

Tags

Communities of Interest

  • Air Platforms
  • C4I

DTIC Thesaurus Topics

  • Aerodynamics
  • Autorotation
  • Computational Fluid Dynamics
  • Equations
  • Flow Rate
  • Fluid Dynamics
  • Fluid Mechanics
  • Frequency
  • Government Procurement
  • Governments
  • Journal Bearings
  • Mathematical Models
  • Mechanics
  • Navier Stokes Equations
  • Pressure Distribution
  • Pressure Gradients
  • Shear Stresses

Readers

  • Electronics Engineering
  • Structural Dynamics.
  • Tribology (the study of the boundary interaction between sliding surfaces, lubrication, wear and friction).

Technology Areas

  • Space
  • Space - Hall-Effect Thruster
  • Space - Orbital Debris