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Tytuł:
The Effect of Cold Eddy on Acoustic Propagation (Case Study : Eddy in the Persian Gulf)
Autorzy:
Mahpeykar, Omid
Ashtari Larki, Amir
Akbari Nasab, Mohammad
Powiązania:
https://bibliotekanauki.pl/articles/31339990.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
Persian Gulf
cold eddy
transmission loss (TL)
acoustic propagation
BELLHOP model
Opis:
It is essential for oceanographers to study the effects of marine phenomena such as currents, surface mixed layer, eddies, internal waves, and other ocean features on acoustic propagation, as most marine measurement equipment operates on this basis, like sonar. The eddy impact on acoustic transmission in the marine environment is very significant because changes in temperature and salinity disrupt the sound speed due to the presence of eddy, thus the acoustic propagation in the sea. Although cold eddies are in the Persian Gulf widely, one eddy is selected to study their impacts on acoustic propagation because they have similar properties in terms of temperature and salinity. In this research, after identifying eddies in the Persian Gulf automatically, the effect of a cold eddy on acoustic propagation was investigated at different depths using the BELLHOP model. Most eddies are cyclonic with 5–10 km of radius based on algorithm outputs. Studies on the lifespan of eddies showed that the occurrence of cyclonic eddies with a lifespan of more than three days is more than anticyclonic ones. Examination of the eddy effect on acoustic propagation showed that the transmission loss (TL) during the progress of the acoustic wave across the eddy increases with increasing the depth of the sound source. Also, the presence of cold eddy compared to the conditions it does not exist increases the transmission loss. The study of three-dimensional acoustic propagation also confirmed the obtained results in two-dimensional mode and clearly showed the role of cold eddy in increasing the TL.
Źródło:
Archives of Acoustics; 2022, 47, 3; 413-423
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Technical Notes : Practical Concerns Associated with Single-Number Ratings in Measuring Sound Transmission Loss Properties of Partition Panels
Autorzy:
Garg, N.
Kumar, A.
Maji, S.
Powiązania:
https://bibliotekanauki.pl/articles/177637.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Sound Transmission Loss
Sound Transmission Class
spectrum adaptation terms
ISO 717-1
weighted sound reduction index
spectrum adaptation term corresponding to noise source
Cx
TL
STC
Opis:
The paper presents an extensive review investigating the practical aspects related to the use of single- number ratings used in describing the sound insulation performance of partition wall panels and practical complications encountered in precise measurements in extensive frequency range from 50 Hz to 5 kHz. SWOT analysis of various single number ratings is described. A laboratory investigation on a double wall partition panel combination revealed the significant dependence of STC rating on transmission loss at 125 Hz attributed to 8 dB rule. An investigation conducted on devising alternative spectrums of aircraft noise, traffic noise, vehicular horn noise and elevated metro train noise as an extension to ISO 717-1 Ctr for ascertaining the sound insulation properties of materials exclusively towards these noise sources revealed that the single-number rating Rw + Ctr calculated using ISO 717-1 Ctr gives the minimum sound insulation, when compared with Rw + Cx calculated using the alternative spectrums of aircraft noise, traffic noise, etc., which means that material provides a higher sound insulation to the other noise sources. It is also observed that spectrum adaptation term Cx calculated using the spectrum of noise sources having high sound pressure levels in lower frequencies decreases as compared to ISO 717-1 Ctr owing to significant dependence of Ctr at lower frequencies.
Źródło:
Archives of Acoustics; 2013, 38, 1; 115-124
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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