Very low‐frequency underwater sound propagation loss predictions for the NOSC tower site off Mission Beach, California

1978 ◽  
Vol 63 (S1) ◽  
pp. S62-S62
Author(s):  
J. Northrop
Keyword(s):  
Sound Propagation ◽  
Low Frequency ◽  
Propagation Loss ◽  
Underwater Sound ◽  
Very Low Frequency

Flow-dependent modeling of acoustic propagation based on DG-FEM method

2021 ◽  
Author(s):  
Zichen Wang ◽  
Jian Xu ◽  
Xuefeng Zhang ◽  
Can Lu ◽  
Kangkang Jin ◽  
...  
Keyword(s):  
Sound Propagation ◽  
Transmission Loss ◽  
Acoustic Propagation ◽  
Water Area ◽  
Current Speed ◽  
Propagation Model ◽  
Propagation Loss ◽  
Two Dimensional ◽  
Underwater Sound ◽  
Ocean Environment

AbstractThis paper proposes a two-dimensional underwater sound propagation model using the Discontinuous Galerkin Finite Element Method (DG-FEM) to investigate the influence of current on sound propagation. The acoustic field is calculated by the convected wave equation with the current speed parameter. Based on the current speed data from an assimilation model, a two-dimensional coupled acoustic propagation model in the Fram Strait water area is established to observe the variability in propagation loss under different seasonal velocities in the real ocean environment. The transmission loss and signal time structure are examined. The results obtained in different source frequencies are also compared. It appears that the current velocity, time and range variation all have an effect on underwater sound propagation.

scholarly journals A Composite Perforated Partitioned Sandwich Panel With Corrugation for Underwater Low-Frequency Sound Absorption

2021 ◽  
Vol 7 ◽  
Author(s):  
Junyi Wang ◽  
Jiaming Hu ◽  
Yun Chen
Keyword(s):  
Acoustic Wave ◽  
Composite Structure ◽  
Sound Absorption ◽  
Low Frequency ◽  
Propagation Loss ◽  
Sound Waves ◽  
Acoustic Metamaterials ◽  
Underwater Sound ◽  
Underwater Acoustic ◽  
Frequency Sound

Underwater acoustic wave absorption and control play an important role in underwater applications. Various types of underwater acoustic metamaterials have been proposed in recent years with the vigorous development of acoustic metamaterials. Compared with airborne sound, underwater sound waves have a longer wavelength and much smaller propagation loss, making them more difficult to control. In addition, given that the acoustic impedance of water is much greater than that of air, numerous conventional materials and structures are not suited to underwater use. In this paper, we propose a composite structure based on an excellent broadband low-frequency sound absorber of air using aluminum mixed with rubber. Our composite structure possesses broadband low-frequency (<1,000 Hz) sound absorption underwater, omnidirectional high sound absorption coefficient under the oblique incidence (0–75°), and pressure resistance. It has promising applications for underwater acoustic wave control and contributes to the design of underwater acoustic metamaterials.

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