Numerical Prediction of Propeller Underwater Radiated Noise
The underwater radiated noise (URN) has become a significant issue in the last few decades because of the substantial increase in noise levels in the world oceans. This increased noise level induced by the shipping activities is deemed a potential threat to the marine ecosystem. A ship has different noise sources such as machinery & auxiliary engine noise, flow-induced noise, non-cavitating and cavitating propeller radiated noise. Amongst these sources, if present, cavitation on and of the propeller blades is a crucial noise source contributing to the overall radiated noise levels. Therefore, the accurate prediction of the propeller URN is an important research area in the maritime field.
Fig.1 The comparison of CFD and experiment in terms of sheet and tip vortex cavitation. Fig. 2 The mitigation of tip vortex cavitation with the roughness application.
Fig. 3. The comparison of CFD and experiment in terms of the propeller URN. Fig. 4. The visualisation of the coherent vortex structure in the propeller`s slipstream using CFD.
Within the above framework, Savas Sezen’s PhD with the above title in the Department of Naval Architecture, Ocean and Marine Engineering at the University of Strathclyde has been making use of ARCHIE-West to explore the marine propeller underwater radiated noise (URN) under non-cavitating and cavitating conditions. The current research in the hydroacoustic field focuses on predicting propeller URN in the model and full-scale in the real-world scenarios. The cavitation, particularly tip vortex cavitation (TVC), has been modelled using the developed advanced meshing technique to reflect the realistic conditions. Also, the roughness has been included in the calculations to investigate its effects on tip vortex flow, TVC and hence propeller URN using wall function approach and modelling the physical roughness. Thus, the roughness has been implemented at the strategical areas on the propeller blades to mitigate the TVC, hub vortex cavitation and hence propeller URN as a passive noise control method. The Computational Fluid Dynamic (CFD) simulations have been conducted using RANS, DES and LES methods. The outcomes of this research have been published in several journals and international conferences. In addition to this, the important findings of this research have contributed to EU research projects.
For more information about the project contact Prof. Mehmet Atlar (email@example.com), Professor at the Department of Naval Architecture and Marine Engineering at the University of Strathclyde.
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