Cavitation extension overview

Noise measurements of a cavitating propeller in different facilities, new paper

SSPA participates in several international research collaborations with the aim of improving experimental methods. To better understand the accuracy and reliability of underwater radiated noise (URN) measurements, a test programme to compare results among several institutes was organized within the CoP Noise (Community-of-Practice “Noise”) by the Hydro Testing Forum, where SSPA is a partner. The well-known journal Ocean Engineering has published a new paper in the October issue.

In the last decade there has been a rising interest of noise measurements and the understanding of the underlying mechanisms of noise generation and radiation. Our experts continuously strive to improve the methods for predicting underwater radiated noise (URN). Within the international network Hydro Testing Forum (HTF) SSPA are contributing with more research in this area.

In the paper, the CoP Noise (Community-of-Practice “Noise”) has developed, organized and performed a round robin (RR) test programme about the URN (underwater radiated noise) of a propeller operating in open water with horizontal and inclined shaft under different loading conditions. The RR test programme involves various facility types ranging from small- to large-scale cavitation tunnels, and facilities such as a free-surface cavitation channel and a depressurized towing tank. 

About the paper

The paper: “Noise measurements of a cavitating propeller in different facilities: Results of the round robin test programme”, published in Ocean Engineering, Volume 213, 1 October 2020. 

Authors: Giorgio Tani, Department of Electrical, Electronic, Telecommunication Engineering and Naval Architecture, Universit`a degli Studi di Genova (UNIGE), Italy, Michele Viviani, Naval Architecture, Universit`a degli Studi di Genova (UNIGE), Italy, Mario Felli, Istituto di ingegneria del Mare (CNR-INM), Italy, Frans Hendrik Lafeber, Maritime Research Institute Netherlands (MARIN), the Netherlands, Thomas Lloyd Maritime Research Institute Netherlands (MARIN), the Netherlands, Batuhan Aktas, Naval Architecture, Ocean and Marine Engineering, University of Strathclyde (UoS), UK, Mehmet Atlar Ocean and Marine Engineering, University of Strathclyde (UoS), UK, Serkan Turkmen, School of Engineering, Newcastle University (UNEW), UK, Marine, Offshore & Subsea Technology Group, Newcastle University (UNEW), UK, Hanshin Seol, Korea Research Institute of Ships & Ocean Engineering (KRISO), South Korea, Jan Hallander, SSPA, Sweden, Nobuaki Sakamoto, National Maritime Research Institute (NMRI), Japan.

Abstract

Mitigation of shipping noise is a topical issue in marine engineering because of the dramatic increase in the levels of anthropogenic underwater noise and its impact on marine life. In recent years, hydro-acoustic research has focussed on the development of reliable methods for predicting underwater radiated noise (URN) due to cavitation, which is known to be the dominant contribution to the overall radiated noise spectrum of ships above the cavitation inception threshold. Model-scale measurements are currently considered the most reliable approach to study URN problems in marine engineering and are crucial for the verification and validation of numerical methods. However, their reliability is affected by several uncertainty sources for which suitable test procedures and post-processing techniques are needed. As a means to better understand the accuracy and reliability of underwater radiated noise measurements, a round-robin (RR) test programme for an open water propeller setup was organized within the Community-of- Practice “Noise” of the Hydro Testing Forum, with the aim of comparing results among several institutes (i.e. University of Genova UNIGE, University of Newcastle UNEW, NMRI, SSPA, KRISO, CNR-INM and MARIN). This paper reports an overview of the RR programme and compares the different approaches and results.

The article is available online at www.sciencedirect.com

Photos

Cavitation extents observed at SSPA for all the operational conditions, with the level shaft.