Progress in the prediction and mitigation of propeller cavitation noise and vibrations

Comfort on board passenger vessels and pleasure craft is a primary design consideration. Furthermore, underwater radiated noise from vessels is receiving increasing attention due to the impact on marine life, resulting in the development of associated guidelines and regulations.
One of the primary sources of ship noise and vibration is propeller cavitation. The highest broadband noise levels typically originate from the cavitating tip vortex, which has recently received significant attention at MARIN. This has resulted in more knowledge of its behaviour and in improved prediction methods. These methods are used as part of both experimental and numerical studies related to assessing cavitation hindrance.
Noise and vibration performance can also be targeted during the design phase, for example, through improved propeller design, in which a trade-off between efficiency and cavitation hindrance is considered. An alternative or complementary mitigation approach is the use of air injection systems, which can potentially be retrofitted.
This paper gives an overview of recent activities at MARIN related to the improved prediction and mitigation of noise and vibration generated by cavitating propellers, including examples of experimental and numerical predictions, propeller design and optimisation studies, and modelling of air injection systems.