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    Tytuł:
    Spatial distribution of underwater sound generated by hull of moving ship
    Autorzy:
    Listewnik, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/332792.pdf
    Data publikacji:
    2009
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Tematy:
    underwater sound
    ship
    acoustics
    Opis:
    The paper presents the experimental research associated with the spatial distribution of acoustic energy generated by moving ship into the water. The paper present the methodology of evaluations acoustics energy from the mechanisms of ship into the water environment. For that purpose the research of noise spatial distribution over ship's hull were conducted along with the hydroacoustic field. The hull is source of waves of complex surface shape inducing waves of different amplitudes and phases depending on the position of ship's machinery. As a result of the hull vibrations generated wave distribution depending on the primary sources, as the main propulsion units, generators or other mechanisms. This research allowed to determine position of the main noises' sources of acoustics energy of machinery and propulsion system depending on class of ships and to designate spatial distribution of noise generated by hull of moving ship.
    Źródło:
    Hydroacoustics; 2009, 12; 109-116
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Repellence Effect of the New Sound for Underwater Speaker of Hydrofoil
    Autorzy:
    Nakashima, T.
    Kobayashi, N.
    Yamada, H.
    Katsumata, T.
    Yoshida, R.
    Kato, H.
    Okabe, H.
    Kawazu, I.
    Yanase, Y.
    Omine, M.
    Terada, M.
    Sugioka, H.
    Kyo, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/116522.pdf
    Data publikacji:
    2015
    Wydawca:
    Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
    Tematy:
    Underwater Speaker (UWS)
    Hydrofoil
    Underwater Speaker Sound
    Humpback Whale
    New Sound
    Cetaceans
    Acoustics
    Hydroacoustics
    Opis:
    In order to prevent hydrofoil colliding with cetaceans, the underwater speaker (UWS) has been installed to repel cetaceans. Yamada et al. (2012) analyzed and devised the UWS sound as it fits the cetaceans' acoustic properties to prevent the collision furthermore. The new UWS sound was devised and synthesized by Yamada et al. (2015) with expectation of avoiding collision with large cetaceans (Patent applied for, JP2014-171411). In this research project, the new UWS sound was investigated by the playback experiment on humpback whale (Megaptera novaeangliae) and by sighting survey in the actual hydrofoil shipping service route. As a result, a physiological and behavioral change of the humpback whale was observed in the playback experiment of the new UWS sound, and the chance of hydrofoil encountering cetaceans of the new UWS sound was smaller than that of the previous UWS sound. Therefore, the improvement of the new UWS sound was confirmed. Lastly, we wish this research project would contribute toward the safer cruise of hydrofoil in the future.
    Źródło:
    TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2015, 9, 2; 207-211
    2083-6473
    2083-6481
    Pojawia się w:
    TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wpływ podwodnej fali akustycznej na bezpieczeństwo i zdrowie nurka - uwagi ogólne
    The influence of the underwater sound-wave on the safety and the health of the diver - general remarks
    Autorzy:
    Konarski, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/366344.pdf
    Data publikacji:
    2010
    Wydawca:
    Polskie Towarzystwo Medycyny i Techniki Hiperbarycznej
    Tematy:
    podwodna fala akustyczna
    sonar
    nurek
    nurkowanie
    bezpieczeństwo nurkowania
    underwater sound-wave
    diver
    diving
    diving safety
    Opis:
    Wiadomo powszechnie, iż nadmierna ekspozycja na oddziaływanie energii akustycznej wiązać się może z szeregiem niekorzystnych następstw dla organizmu człowieka. Nie inaczej jest w przypadku oddziaływania podwodnej fali akustycznej na nurka, przebywającego w zanurzeniu. Najczęstszym źródłem fal o parametrach, mogących zagrozić zdrowiu lub życiu nurka, są wybuchy podwodne i sonary. W artykule, w oparciu o przegląd wybranego piśmiennictwa, scharakteryzowano potencjalne zagrożenia dla zdrowia i życia nurka, wynikające z oddziaływania podwodnej fali akustycznej, generowanej przez urządzenia sonarowe oraz wskazano na możliwości biernej i czynnej profilaktyki w tym zakresie.
    It is known universally, that the excessive exposition on the influence of the acoustic energy join one can with the row of unprofitable results for the organism of the man. Not otherwise it is in the case of the influence of the underwater sound-wave on the diver, spending in the dip. The most frequent source of waves about parameters, liable to threaten to the health or life of the diver, are underwater explosions and sonars. In the article, basing on the review of the chosen literature, author characterized potential hazards for health and life of the diver, consequential from the influence of the underwater sound-wave, generated by sonar devices and evidenced possibilities of the passive and active prophylaxis in this range.
    Źródło:
    Polish Hyperbaric Research; 2010, 2(31); 7-13
    1734-7009
    2084-0535
    Pojawia się w:
    Polish Hyperbaric Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Development of the Effective Underwater Speaker Sound Modulated by Audible Sound Frequency Range of Large Cetaceans for Avoidance with Ship Collision
    Autorzy:
    Yamada, H.
    Kobayashi, N.
    Nakashima, T.
    Kato, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/116934.pdf
    Data publikacji:
    2015
    Wydawca:
    Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
    Tematy:
    Cetaceans
    Underwater Speaker (UWS)
    Underwater Speaker Sound
    Audible Sound Frequency Range
    Hydrofoils
    Hydroacoustics
    Avoidance with Ship Collision
    Large Cetaceans
    Opis:
    The underwater speaker (UWS) has been installed on high speed vessels; hydrofoils (HF) with low-noise during their cruises, to avoid sudden collisions with large cetaceans, while its performance has remained uncertain because of the problem in quality of the produced sound. Thus, we developed a sound source for the UWS by modulating the sound based on the audible range of major large cetaceans so as to increase its utilities. To investigate the audible sound frequency range of cetacean, we tried two procedures, (1) indirect-estimation from relationship between cetaceans audibility and vocalization, and (2) indirect-estimation from measurements on the cochlear basal membrane. We also synthesized the two new sound sources which we can potentially expect an avoidance with large cetaceans. Through several field experiments with deploy the new sounds we reached a tentative conclusion that the new sound was effective in terms of inducing the cetaceans' avoidance reaction and would be also expected to be applied to other low-noise vessels.
    Źródło:
    TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2015, 9, 2; 213-217
    2083-6473
    2083-6481
    Pojawia się w:
    TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Ships underwater noise measurements using sound intensity method
    Autorzy:
    Gloza, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/332552.pdf
    Data publikacji:
    2009
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Tematy:
    underwater noise
    ships
    sound intensity method
    Opis:
    Ship noise is a most important part of the field of underwater acoustics. Its reduction and monitoring is an important aspect in the performance of underwater acoustic systems and in the habitability of the vessel for the crew and passengers. In naval operations the noise radiated by a ship is also dominant source of information for underwater sonar systems. Sound intensity is the vector quantity which informs us about the sound power flux, the position and the direction of the sound source. The probe tracks the position of source and at the same time, measures the component of sound-intensity vector. Generally only one component of vector sound intensity was measured, perpendicular to a given measurement surface. The sound intensity of a moving source includes effects such as flow noise that are not present when the source is stationary. The accuracy of measuring acoustic intensity using two closely spaced hydrophones by correcting the phase mismatch error by measuring the transfer function between the two detector systems was examined. The two measuring hydrophone instrumentation systems were earlier calibrated. Our results have been obtained using digital methods, where was used PULSE measuring system.
    Źródło:
    Hydroacoustics; 2009, 12; 53-60
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Reflection of low-frequency long-range sound in the ocean
    Autorzy:
    Didenkulov, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/332043.pdf
    Data publikacji:
    2003
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Tematy:
    low frequency
    long-range
    sound
    ocean
    underwater
    Opis:
    Experimental results on energetic characteristics of low frequency (about 200 Hz) underwater channel sound reflection by ocean mountains and islands are presented. lt is investigated also sound penetration into shallow water. Transformation of vertical structure of sound field over continental slope is considered. Continental slope and shelf-wedge reflection coefficients of law frequency sound propagating in the underwater waveguide were measured. Results of the work show that low-frequency sound reflections from large-scale bottom irregularities can be important in ocean acoustics.
    Źródło:
    Hydroacoustics; 2003, 6; 117-124
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Statistical Optimization of Underwater Lower-Frequency Sound Insulation for Locally Resonant Sonic Material Using Genetic Algorithm
    Autorzy:
    Yuan, Bo
    Chen, Yong
    Tan, Bilian
    Li, Bo
    Powiązania:
    https://bibliotekanauki.pl/articles/177461.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    underwater acoustic
    sound insulation
    local resonance
    statistical optimization
    global optimum
    Opis:
    The locally resonant sonic material (LRSM) is an artificial metamaterial that can block underwater sound. The low-frequency insulation performance of LRSM can be enhanced by coupling local resonance and Bragg scattering effects. However, such method is hard to be experimentally proven as the Best optimizing method. Hence, this paper proposes a statistical optimization method, which first finds a group of optimal solutions of an object function by utilizing genetic algorithm multiple times, and then analyzes the distribution of the fitness and the Euclidean distance of the obtained solutions, in order to verify whether the result is the global optimum. By using this method, we obtain the global optimal solution of the low-frequency insulation of LRSM. By varying parameters of the optimum, it can be found that the optimized insulation performance of the LRSM is contributed by the coupling of local resonance with Bragg scattering effect, as well as a distinct impedance mismatch between the matrix of LRSM and the surrounding water. This indicates coupling different effects with impedance mismatches is the Best method to enhance the low-frequency insulation performance of LRSM.
    Źródło:
    Archives of Acoustics; 2019, 44, 2; 365-374
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Underwater Noise Generated by a Small Ship in the Shallow Sea
    Autorzy:
    Grelowska, G.
    Kozaczka, E.
    Kozaczka, S.
    Szymczak, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/177360.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    signal processing
    sound propagation
    underwater ship noise
    propagation in the shallow sea
    Opis:
    Study of the sea noise has been a subject of interest for many years. The first works in this scope were published at the turn of the twentieth century by Knudsen (Knudsen et al., 1948) and G. Wenz (Wenz, 1962). Disturbances called “shipping noise” are one of the important components of the sea noise. In this work the results of an experimental research of underwater noise produced by a small ship of a classic propulsion are presented. A linear receiving antenna composed of two orthogonal components was used in the investigation. Identification of the main sources of acoustic waves related with the ship was achieved. In addition, the intensity of the wave was measured. The research was performed in conditions of the shallow sea.
    Źródło:
    Archives of Acoustics; 2013, 38, 3; 351-356
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On the Interaction of Resonance And Bragg Scattering Effects for the Locally Resonant Phononic Crystal with Alternating Elastic and Fluid Matrices
    Autorzy:
    Yuan, B.
    Chen, Y.
    Jiang, M.
    Tang, S.
    He, M.
    Tu, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/177103.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    locally resonant phononic crystals
    effective speed of sound
    coupling band gaps
    underwater acoustic materials
    Opis:
    Three-dimensional (3D) locally resonant phononic crystals (LRPCs) are studied with the aim of optimising the sub-wavelength band gaps of such composites. By analysing their effective acoustic properties, it has been found that the effective acoustic speed of the composite will drop to zero when local resonance arise, and will increase monotonically when Bragg scattering effects occur. Moreover, if the matrix is a low-shear-speed medium, local resonators can significantly reduce the effective acoustic speed of the composite and, therefore, lower the frequency where Bragg scattering effects occur. Hence, a specific LRPC with alternating elastic and fluid matrices is proposed, whose resonance and Bragg gaps are already close in frequency. The fluid matrix behaves as a wave filter, which prevents the shear waves from propagating in the composite. By using the layer-multiple-scattering theory, the coupling behaviour of local resonance and Bragg scattering band gaps has been investigated. Both gaps are enhanced when they move closer to each other. Finally, a gap-coupled case is obtained that displays a broad sub-wavelength band gap. Such proposal excels at the application of underwater acoustic materials since the arrangement of structure can be handily adjusted for tuning the frequency of coupled gap.
    Źródło:
    Archives of Acoustics; 2017, 42, 4; 725-733
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Design Sensitivity Studies on a Hydroacoustic Projector Using an Experimentally Validated Easy-to-Build Model
    Autorzy:
    Sreejith, Vattaparambil Sreedharan
    Tiwari, Nachiketa
    Powiązania:
    https://bibliotekanauki.pl/articles/2141678.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    low frequency sound source
    underwater transducer
    fluid power
    hydro-electro-mechano-acoustic analogy
    hydraulic valve
    piston
    cylinder
    Opis:
    Hydroacoustic projectors are useful for generating low frequency sounds in water. Existing works on hydroacoustic projectors require two significant enhancements, especially for designers. First, we need to understand the influence of important projector design parameters on its performance. Such insights can be very useful in developing a compact and efficient projector. Second, there is a need for an integrated model of the projector based on easily available and user-friendly numerical tools which do not require development of complex customised mathematical analogs of projector components. The present work addresses both such needs. Towards these goals, an experimentally validated, easy-to-build projector model was developed and used to conduct design sensitivity studies. We show that reductions in pipe compliance and air content in oil, and an increase in orifice discharge coefficient can yield remarkable improvements in projector’s SPL. We also show that reductions in pipe length and cylinder diameter cause moderate improvements in performance in mass and stiffness controlled regions, respectively. In contrast, the projector performance is insensitive to changes in pistonic mass, cylinder length, and diaphragm stiffness. Finally, we report that while pipe compliance and air content in oil can sharply alter system resonance, the effects of changes in pipe length and pistonic mass on it are moderate in nature.
    Źródło:
    Archives of Acoustics; 2022, 47, 1; 113-124
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of natural conditions on the imaging of the bottom of the Gdańsk Bay by means of the side scan sonar
    Autorzy:
    Witos-Okrasińska, D.
    Grelowska, G.
    Kozaczka, E.
    Powiązania:
    https://bibliotekanauki.pl/articles/258936.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    side scan sonar imaging
    Gdańsk Bay seabed
    refraction of sound ray in sea
    influence of ship’s movement on the wave on underwater imaging
    Opis:
    The interest in underwater resources is the reason for the development of modern hydroacoustic systems, including side sonars, which find numerous applications such as: research of seabed morphology and sediment characteristics, preparation of sea sediment maps, and even in special cases of biocenoses such as sea grass meadows, detection of specific targets at the bottom such as shipwrecks, mines, identification of suitable sites for maritime infrastructure. Such applications require precise information about the position of the objects to be observed. Errors affecting the depiction of the bottom using hydroacoustic systems can be divided into errors associated with improper operation of measuring and support devices, systematic errors and random errors. Systematic errors result from the changing conditions prevailing in the analyzed environment affecting the measurement system. The errors affecting the correct operation of hydroacoustic systems can include: changing angle of inclination of the beam caused by the vessel’s movement on the wave or refraction connected to changes in the sound speed as the depth function.
    Źródło:
    Polish Maritime Research; 2018, S 1; 104-110
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-12 z 12

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