Study on underwater noise characteristic of ship Structure induced by propeller exciting force

摘要

For the propeller running in the non-uniform wake fluid field, the periods excitation is formed on blade surface other than constant thrust. That excitation transfers from shafting, rear bearing, intermediate bearings and trust bearing supporting to hull structure. Decided by the rotation speed of shafting and the number of propeller blades, the propeller exciting force can be mainly found in low frequency. Such kind of excitation can cause the vibration of whole ship structure. The ship radiates large noise underwater that can promulgate very far. The marine ecological environment will be impacted. In this paper, FEM/BEM is adopted to calculate underwater noise characteristic of ship structure. The propeller, shafting, each bearing supporting and ship structure model are built by finite element method by the fluid structure interaction taken into account. The characteristic of underwater noise transmission function and the characteristic of radiated sound pressure distribution are studied. Then, the differences of ship structure radiated sound caused by power equipment excitation and propeller excitation are studied.