Bifurcating behaviour of a rotor on two-lobe wave squeeze film damper

The dynamics of an unbalanced rigid rotor on squeeze film dampers with two-lobe wave bearings was examined by means of a bifurcation analysis based on numerical continuation and on the assumption of the rotor speed as bifurcation parameter. Further parameters in the study were the angular orientation of the bearing, the wave amplitude of the bearing profile and the gravity residual, while single values were given to the static unbalance and the characteristic bearing parameter. The analysis was necessarily restricted, owing to the multiplicity of quantities that affect the system dynamics. Yet, the obtained results put in evidence the way the two-lobe wave geometry influences the bifurcating behaviour of the system, modifying the length of some unstable branches and the whirling periodicity.