Noise and vibration produced by ships are not only problematic for humans, but also for their surrounding environment. It is well-known that a cavitating ship propeller is the dominant noise source which contributes the Underwater Radiated Noise (URN) level. National and international authorities require the marine industry to run their ships and floating structures in habitability, comfort vibration and noise limits. All issued codes, directives or regulations concerning acceptable noise levels on ships intend to improve measurement techniques, accurate noise prediction programs and hull structure dynamic performance to overcome the noise and vibration problem. The EU addresses at the underwater radiated noise problems within the EC Framework Programme 7 through number of different collaborative projects, one of which is the SONIC project (Suppression Of underwater Noise Induced by Cavitation) which aims to develop tools to investigate and mitigate the underwater radiated noise. SONIC project aims to set up and populate a database of UNR measurements for ships within the framework of the above aim. One of the goals of Work Package 2 (WP2) of the project is to investigate the most effective ways to identify URN level. Therefore, Newcastle University’s research vessel, “The Princess Royal”, which has been considered as the benchmark and target vessel in the SONIC project, was equipped to conduct full-scale experiments by the SONIC members in WP2. The cost effective on-board and off-board measurement devices- such as accelerometers, pressure pulse sensors, microphones, hydrophones and ultrasonic transducers as well as high speed cameras- were used in the these trials which were performed on different operating conditions. Pressure data was analysed in 1/3 Octave band and direct measurement of URN level was corrected for the source level at 1m reference distance analysed in 1/3 octave band according to ANSI standard. The level of cavitation was defined with cavitation observations from the observation window above the propeller. This paper presents outcomes which are discussed to evaluate on-board techniques to quantify and monitor URN.
|Place of Publication||Istanbul|
|Publication status||Published - 28 Sep 2015|
- ship noise
- ship vibration
- underwater radiated noise