STABILITY ANALYSIS OF A RIGID ROTOR SUPPORTED ON HYDRODYNAMIC JOURNALBEARINGS WITH ROUGH SURFACES USING THE STOCHASTIC FINITE-ELEMENT METHOD

The effect of surface roughness on the stability characteristics of hy drodynamic journal bearings has been studied. Roughness has been consi dered to be a stochastic variable, which is stationary, ergodic with m ean zero. Both one-dimensional roughness (longitudinal and transverse) and two-dimensional roughness (isotropic) have been studied using the stochastic finite element method. Journal bearings with different wid th-diameter ratios have also been considered. It is seen that the tran sverse roughness tends to increase the stability (non-dimensional mass parameter) whereas in the case of isotropic roughness there is a decr ease when compared with the smooth bearing. Longitudinal roughness has a marginal effect of decreasing the stability of hydrodynamic journal bearings with rough surfaces.