Noise-assisted response steering for a rotor–stator system

Abstract

In the present article, torsional vibrations and whirling motions of an extended Jeffcott rotor–stator system confined within a fixed stator are numerically explored for both forward and backward whirling motions. The governing equations are constructed in a generalized polar coordinate system for describing non-constant whirling speeds and impact motions. Torsional vibrations and whirling motions are examined by using the derived reduced-order equations. It is found that both forward and backward whirling motions with contact have different, but constant steady state whirling speeds. Furthermore, numerical studies have been undertaken to understand the influence of noise on the system dynamics. The trigonometric representation of non-Gaussian excitation as a harmonic excitation with a random phase modulation is modified by introducing a new state variable. The Euler–Maruyama simulation scheme is used for numerical integration. It is observed that for a low value of friction coefficient, with a sufficient level of noise introduction in the drive speed, the system dynamics for the cases of forward and backward whirling with contact can be significantly influenced. The present studies point to potential beneficial uses of noise modulated rotor drive speeds for controlling rotor–stator contact interactions.