Vibro-acoustic analysis of a cylindrical-conical hull subjected to propeller forces

The radiated noise induced by the unsteady propeller forces is an important part of the vessel's total acoustic radiation. Therefore, understanding the role of propeller-shafting system in force transmission characteristics is necessary investigate the underwater vibro-acoustic responses of a vessel. This study compared the contribution of hull and propeller-shafting system to the radiated sound power under the propeller forces in different directions. First, a finite element/boundary element (FE/BE) model of a hull with relatively detailed substructures was developed to study the system's vibro-acoustic characteristics, in which the pulsating pressure at the propeller blade was transmitted to the hull through the propulsion system. The accuracy of the model was validated by experimental results. Second, finite element/boundary element method (FEM/BEM) was used to study the vibro-acoustic characteristics of the submerged system and the amplification effects of the propeller-shafting system. Finally, the radiated sound power of the propeller and the hull were compared, considering the flow-induced noise generated by the water surrounding the propeller. Results show that while it is reasonable to ignore the sound power generated by the elastic propeller structure, the flow-induced noise still needs to be considered, especially when the forces are applied to the propeller in the transverse and vertical directions. © 2020 Elsevier Ltd