Abstract
In turbomachinery, nonlinearity appears in restoring forces or damping forces due to various causes, such as clearances in bearings, squeeze film dampers, oil films in journal bearings, magnetic forces, seals, frictions and stiffening effect in elongation of a shaft center line. As a result, various kinds of nonlinear phenomena occur. For example, it is known that subharmonic oscillations, summed - and - differential harmonic oscillations, chaotic motions, jump phenomena, and limit cycles occur in rotor systems. In this review article, characteristics of these nonlinear phenomena are outlined and literature on these phenomena is introduced.