Random response of highly skewed propeller-shafting system induced by inflow turbulence

The random responses of a highly skewed propeller-shafting system in both axial and radial direction induced by inflow turbulence are numerically studied. Firstly, a fine finite element model is established, including propeller, shaft and surrounding fluid. The force-force transfer function matrix between each exciting node on the blade surfaces and the corresponding transmitted force is formed based on the FEM model. Secondly, the unsteady hydrodynamic pressure spectrum acting on the blade surface is calculated on the basis of strip theory and mapped onto all nodes that distribute on the blade surfaces. Finally, the random response of the system and the power spectral densities of the transmitted forces from both axial and radial bearings are obtained. By employing the numerical method, the relationship between the force amplification effect and the modal characteristics of the highly skewed propeller-shafting system is discussed. Furthermore, the influence of system dynamic parameters, such as propeller elasticity, axial and radial bearing stiffness on the random vibration is analyzed, which can thus provide a reference for the design of low noise propulsion system for ships.