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Item type:Publication, Access status: without files , Experimental and numerical advances in underwater radiated noise prediction of cavitating propeller-hull combinations(International Commission for Acoustics (ICA), 2022-06); ; ; ; Propeller induced cavitation is the primary underwater radiated noise source of motorized shipping activities, which coincides with acoustic frequencies utilized by marine life and may therefore have negative impacts on the ecosystem. This paper is the conclusion of the research project ProNoVi introduced at ICA2019 and presents the final results of both experimental and numerical campaigns on a high-level for all participants. While propulsion related phenomena are analyzed based on evaluation of high-speed recordings, the focus lies on model and full scale comparisons of acoustic measurements with pressure pick-ups and hydrophones in the far-field. Accompanying simulations with active phase transition are undertaken, by employing high fidelity CFD methods with RANS and scale resolved DES or LES turbulence modelling. For different methods and setups, the emitted noise from the propeller and its slipstream, where induced vorticity and cavitation-dynamics play an important role, are compared for an openwater propeller case and several propeller-hull combinations. The analysis of these workflows on real propeller-ship combinations reveal adequate results, regarding comparability and reproducibility between different experimental and numerical setups and point to future opportunities for the improvement of accurate underwater noise predictions while saving numerical and experimental resources.Publicationtype: Conference Paper81 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Advances toward Numerical Prediction of Noise Emitted by Yacht and Passenger Ship PropellersThe radiated underwater noise due to shipping activities raises considerably the natural underwater background noise level. With an estimated increase of about 3dB per decade, this development is extremely fast in comparison with evolutionary timescales for some of the affected sea fauna to adapt. Low frequency radiated noise covering the 63 Hz to 125 Hz 1/3 octave bands is dominated by propeller cavitation. At the same time, the highest levels of on-board noise are reportedly noted in the same lower-frequency bands, and they are thus also attributed to propeller cavitation. The present paper addresses the following main problems whose solution is critical for the adequate prediction of propeller acoustic performance using numerical approaches: 1) resolution of anisotropic fields of turbulence in the vicinity of propeller-induced vorticity; 2) prediction of dynamic behaviour of cavitation on propeller blades and in propeller-induced vortices; 3) solution of acoustic propagation in the ambient flow domain. Presenting the state-of-the-art in the field, the paper is further focused on the ongoing research and advances regarding the solution of the aforementioned problems in the R&D project ProNoVi. In particular, the aspects related to the use of scale resolving CFD simulations and implementation of acoustic analogy techniques with both the viscous flow and potential flow hydrodynamic solutions are discussed. The examples of validation studies are presented. The project ProNoVi (http://www.pronovi.eu/) is supported and funded by the MarTERA ERA-NET program, represented by BMWi-project (03SX461C) “ProNoVi” for the German partners (TUHH, Fr. Lürssen Werft GmbH & Co. KG, SCHOTTEL GmbH), the Research Council of Norway "Project 284501" for the Norwegian Partners (SINTEF Ocean, Helseth AS) and MIUR-project “ProNoVi” for the Italian partners (CNR-INM).Publicationtype: Conference Paper170 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Analysis Methods and Design Measures for the Reduction of Noise and Vibration Induced by Marine Propellers(Deutsche Gesellschaft für Akustik, 2019-09); ; ; ; The paper presents the ongoing work in the research project ProNoVi. The objective of the project is to improve the numerical and experimental methods for the prediction of noise and vibrations induced by a propeller operating behind ship hull in full-scale conditions. Based on the improved methods practical recommendations for the reduction of noise and vibration levels for diơerent classes of vessels are a further objective. The propeller cavitation noise is identified as the dominating noise source, which coincides with important frequencies of perception of marine fauna and thus may have negative impact on marine life. As a side eơect, reducing the noise under water will increase comfort and thus safety for crew and passengers on board. The project aims at delivering a better understanding of fundamental physical mechanisms related to turbulence, induced vorticity and cavitation dynamics, which play a decisive role in generation of tonal and broadband propeller noise. The project partners will give a joint presentation, focusing on state-of-the-art in the field, today’s challenges in both the experimental and numerical approaches, and how the ProNoVi project is addressing those. ProNoVi is funded by the European Union. Further information is available at www.martera.eu/projects/pronovi.Publicationtype: Conference Paper95 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Influence of Flow Transition on Open and Ducted Propeller CharacteristicsPublicationtype: Conference Paper57