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1

Low to middle vibro-acoustic noise prediction in ship cabin by using plate-cavity coupling model

Zhou Z., Wu J.

Polish Maritime Research

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2018

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S 2

149--157

EN

A plate-cavity coupling method based on modal expansion technique in the closed sound cavity was introduced, aiming at ship cabin structural noise. Using this method, a coupled equation was established. The structural vibration acceleration of the target cabin was extracted from a ship vibration response calculation, applied to the model. Then the target cabin noise value was obtained through numerical calculation. The effectiveness and reliability of the method were validated through experiments. The coupled model predicts noise in the cabin does not require fluid finite element model of the cabin air, thus greatly reducing the calculation time compared with the pure finite element method. It was shown that the method is suitable for the calculation of noise in a single ship cabin; the method has a high calculation efficiency. Furthermore, the calculated result is a continuum. On the one hand, it can be conveniently converted to an octave or 1/3 octave according to the specification. On the other hand, the form of the continuum also provides a corresponding response to the subsequent vibration and noise control.

2

Study of Noise Propagation for Small Vessels

Weryk M., Kozaczka E., Grelowska G.

Archives of Acoustics

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2015

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Vol. 40, No. 2

267--272

EN

The paper presents the results of the noise propagation analysis in ship structures tested in a number of AHTS (Anchor Handling Tug Supply) vessels. Statistical Energy Analysis (SEA) based on numerical model developed specially for the purpose of this numerical investigation were conducted. This numerical model enabled the analysis of both the structural elements and the acoustic spaces. For the detailed studies 47 points fixed at various ship locations were selected. Prediction results with use of the numerical model were compared with the experimental results carried out in six identical AHTS vessels. Experimental studies were performed in accordance with the requirements of the International Maritime Organization (IMO) Resolution A.468 (XII). As a result one presented a comparison of the model analysis and experimental tests results.

3

Sound Emitted by Ships and Grey Seals into Water Environment

Gloza I.

Mechanika / Akademia Górniczo-Hutnicza im. St. Staszica

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2004

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T. 23, z. 2

161-168

EN

In this paper we give a brief introduction to the marine behaviour of the grey seals and describe the current state of knowledge about their hearing and influence of ship noise into their life. The Naval University had the opportunity to record these sea mammals vocalizations in the Polish peninsula Hel. The waters of the Baltic Sea are major area for shipping, military exercises and activities including: merchant vessels movement, surface warships and submarines exercises, torpedo testing and firing ranges, therefore they are full of noise. Ship noise spectra are usually in two categories: broad-band noise, which has a continuous spectrum; and tonal noise, which contains discrete frequencies or lines. Additionally the acoustic radiation is also characterized by passing and irregular noise caused by impacts, loose equipment and machinery changes of state. Propeller cavitation is also a major problem here.

PL

Dźwięki emitowane przez obiekty podwodne są źródłem fal akustycznych rozchodzących się w środowisku wodnym. Proces ten może mieć szkodliwy wpływ na równowagę ekologiczną, zwłaszcza w przypadku takich źródeł jak statki i okręty, w akwenach o dużym nasileniu ruchu. Głównym celem artykułu jest przedstawienie wyników obszernych badań doświadczalnych związanych z transmisją do wody energii akustycznej przez jednostki pływające. W pracy przedstawiono metodykę oceny transmisji do wody energii drgań mechanizmów okrętowych znajdujących się wewnątrz kadłuba. Przedstawiono również wyniki badań dźwięków emitowanych przez fokę szarą w postaci wąskopasmowych widm mocy. Mając na uwadze, że rozkład drgań na powierzchni kadłuba, a także warunki propagacji fal akustycznych w morzu płytkim są procesami nieliniowymi, zależnymi od wielu czynników, wnioski oparto głównie na wieloletnich badaniach prowadzonych w warunkach naturalnych.