Revisiting Rotor Rigid Body Modes: Parametric Study of Stability

Abstract

This paper presents an analytical model of a rigid rotor supported in two fluid film bearings with an emphasis on predicting the instability threshold speed. The factors contributing to the stability of the rotor are discussed and presented graphically using root locus plots. The parametric study of the stability starts from the discussion of the rotor/bearing system with “mirror symmetry”. Three basic cases are considered:

Keywords

• Gyroscopic
• Fluid bearing
• Optimal design
• Stability
• Root locus.