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Wyszukujesz frazę "shallow underwater acoustic" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Investigation of the vertical distribution of the sound speed of the Gulf of Gdansk in the years 2000-2010
Autorzy:
Grelowska, G.
Witos, D.
Powiązania:
https://bibliotekanauki.pl/articles/332481.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
shallow water acoustics
underwater acoustic climate
Opis:
The conditions of the acoustic wave propagation in the southern Baltic are much more complex than in other shallow waters. In the typical shallow water, seasonal changes in acoustical conditions in the upper layer, of the depth of about 60-70 m, are observed. They are caused by variation of the annual meteorological conditions. Most often, in the deep water layer, acoustical conditions are stable throughout the year. However, in the Southern Baltic they change during the year also in the deep water layer. They depend on the inflows of highly saline water from the Northern Sea through the Danish Straits, which evoke a dense bottom current increasing the salinity at the bottom. The vertical sound speed distribution in the Southern Baltic is strongly dependent on the hydrological conditions. In the paper the characteristic elements of acoustic climate of the Southern Baltic will be considered, based on data concerning the Gulf of Gdansk. Averaged characteristics of temperature, salinity and sound speed for the years 2000-2010, as well as anomalies, have been determined.
Źródło:
Hydroacoustics; 2016, 19; 129-137
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Propagation of ship-generated noise in shallow sea
Autorzy:
Kozaczka, E.
Grelowska, G.
Powiązania:
https://bibliotekanauki.pl/articles/259166.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
shallow water acoustics
propagation of acoustic waves in water layer
wave modes in shallow sea
underwater noise produced by ship
Opis:
Contamination of sea environment by noise and any energy radiated to water constitutes today a problem to which more and more attention is paid, in view, a.o., of consequences of an impact of these factors onto marine fauna. European Union has introduced a directive by which EU countries are made responsible to undertake efforts aimed at reaching a good envirenmental status of European seas by 2020. A main source of underwater noise is sea transport of any kind. Propagation of underwater acoustic disturbances in the Baltic Sea highly differs from the course of the phenomenon in a deep sea. Model of spherical propagation cannot be applied to this case in view of water environment limitation by seabed and free water surface, i.e. a reduction of the problem to wave propagation in a water layer of the depth comparable with acoustic wave length. This paper is aimed at demonstration of possible assessment of range of acoustic disturbances generated by a ship sailing in shallow sea, by using a method described in the work [13]. The research was made on the basis of results of own measurements of underwater noise produced by ships in the Gdansk Bay area. An important factor which decIdes on a range of underwater disturbances is a kind of seabed sediments. In this paper there are presented results of numerical investigations based on real data dealing with noise produced by a selected floating unit (ship) for selected characteristic spectral components. The simulations were conducted for the shallow sea model of definite physical parameters such as acoustic wave propagation velocity, geometrical dimensions (water depth) and seabed acoustic parameters as well.
Źródło:
Polish Maritime Research; 2018, 2; 37-46
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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