Underwater Noise Reduction of Offshore Wind Turbines through Vibration Isolation

With the development of ocean renewable energy, offshore wind power has been widely recognized. More and more wind turbines have been built in the offshore area. However, there would be annoying noise during the operation of the wind turbines. A large part of the vibration and noise of the turbine will radiate directly into seawater through the tower, which is potentially harmful to the marine organisms. Therefore, it is necessary to prevent the vibration energy transmission through the tower with vibration isolation design. For one degree-of-freedom (DOF) vibration isolation system, the stiffness of the isolator has to be lower enough to obtain better effectiveness; however, such type of the isolator has soft support, which affects the stability of mechanical system and is not suitable for large equipment. While, for multi-DOF vibration isolation system, the vibration energy transmission characteristics are quite complicated. Therefore, this paper provides the derivation process of analytical solution of the multi-DOF vibration isolation system, which could provide analytical guidance for researchers to decrease the vibration transmission through ocean engineering structures to the ocean, resulting in less noise radiation to the marine environment.