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

• The dynamics of a rotor on SFD with 2lobe-waved bore of the bush is studied.
• Wave amplitude and orientation angle characterize the geometry of the damper bush.
• A bifurcation analysis has been carried out through numerical continuation.
• Wave profile and gravity residual affect the stabilityof the system response.The bone structure of the circular bush dynamics is quite maintained by the 2lobe bush.

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.