Rotor mass effect on nonlinear dynamic behavior of aerodynamic noncircular journal bearing systems



This paper presents the effect of rotor mass on nonlinear dynamic behavior of a rigid rotor supported by aerodynamic noncircular journal bearings. A finite element method has been employed to solve the Reynolds equation in static and dynamical states and the dynamical equations are solved using Runge-Kutta method. To analyze the behavior of the rotor center in horizontal and vertical directions under different operating conditions, dynamic trajectory, power spectra, Poincare maps and bifurcation diagrams are used. Results of this study reveal how the complex dynamic behavior of two types of noncircular bearing systems comprising periodic and -periodic responses of the rotor center varies with changes in rotor mass values.