scholarly journals Parametric spatial post-filtering utilising high-order circular harmonics with applications to underwater sound-field visualisation

2021 ◽  
Vol 149 (6) ◽  
pp. 4463-4476
Author(s):  
Vasileios Bountourakis ◽  
Leo McCormack ◽  
Mathias Winberg ◽  
Ville Pulkki
Keyword(s):  
Sound Field ◽  
High Order ◽  
Underwater Sound

scholarly journals Spiral Sound Wave Transducer Based on the Longitudinal Vibration

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3674 ◽  
Author(s):  
Wei Lu ◽  
Yu Lan ◽  
Rongzhen Guo ◽  
Qicheng Zhang ◽  
Shichang Li ◽  
...  
Keyword(s):  
Sound Wave ◽  
Longitudinal Vibration ◽  
Three Dimensional ◽  
Low Frequency ◽  
Sound Field ◽  
Field Measurements ◽  
Sound Waves ◽  
Underwater Sound ◽  
Three Dimensional Finite Element ◽  
Wave Transducer

A spiral sound wave transducer comprised of longitudinal vibrating elements has been proposed. This transducer was made from eight uniform radial distributed longitudinal vibrating elements, which could effectively generate low frequency underwater acoustic spiral waves. We discuss the production theory of spiral sound waves, which could be synthesized by two orthogonal acoustic dipoles with a phase difference of 90 degrees. The excitation voltage distribution of the transducer for emitting a spiral sound wave and the measurement method for the transducer is given. Three-dimensional finite element modeling (FEM)of the transducer was established for simulating the vibration modes and the acoustic characteristics of the transducers. Further, we fabricated a spiral sound wave transducer based on our design and simulations. It was found that the resonance frequency of the transducer was 10.8 kHz and that the transmitting voltage resonance was 140.5 dB. The underwater sound field measurements demonstrate that our designed transducer based on the longitudinal elements could successfully generate spiral sound waves.

Measurements of the Underwater Sound Field Generated by Quartz Transducers

1951 ◽  
Vol 23 (2) ◽  
pp. 168-172 ◽  
Author(s):  
Winfield Keck ◽  
G. S. Heller ◽  
A. O. Williams
Keyword(s):  
Sound Field ◽  
Underwater Sound

HIGH-ORDER ACCURATE NUMERICAL SCHEMES FOR THE PARABOLIC EQUATION

2005 ◽  
Vol 13 (04) ◽  
pp. 613-639 ◽  
Author(s):  
EVANGELIA T. FLOURI ◽  
JOHN A. EKATERINARIS ◽  
NIKOLAOS A. KAMPANIS
Keyword(s):  
Parabolic Equation ◽  
Finite Difference ◽  
Numerical Solutions ◽  
Finite Difference Methods ◽  
High Order ◽  
Curvilinear Coordinates ◽  
Underwater Sound ◽  
Numerical Schemes ◽  
Implicit Methods ◽  
Simple Boundary

Efficient, high-order accurate methods for the numerical solution of the standard (narrow-angle) parabolic equation for underwater sound propagation are developed. Explicit and implicit numerical schemes, which are second- or higher-order accurate in time-like marching and fourth-order accurate in the space-like direction are presented. The explicit schemes have severe stability limitations and some of the proposed high-order accurate implicit methods were found conditionally stable. The efficiency and accuracy of various numerical methods are evaluated for Cartesian-type meshes. The standard parabolic equation is transformed to body fitted curvilinear coordinates. An unconditionally stable, implicit finite-difference scheme is used for numerical solutions in complex domains with deformed meshes. Simple boundary conditions are used and the accuracy of the numerical solutions is evaluated by comparing with an exact solution. Numerical solutions in complex domains obtained with a finite element method show excellent agreement with results obtained with the proposed finite difference methods.

Sensing the underwater sound field produced by a moving airborne signal source

2009 ◽  
Author(s):  
Brian G. Ferguson ◽  
Kam W. Lo ◽  
Gary C. Speechley
Keyword(s):  
Sound Field ◽  
Signal Source ◽  
Underwater Sound

scholarly journals Quantifying the contribution of ship noise to the underwater sound field

2020 ◽  
Vol 148 (6) ◽  
pp. 3863-3872
Author(s):  
Najeem Shajahan ◽  
David R. Barclay ◽  
Ying-Tsong Lin
Keyword(s):  
Sound Field ◽  
Underwater Sound

Biophysics of underwater hearing in anuran amphibians

1982 ◽  
Vol 98 (1) ◽  
pp. 49-66
Author(s):  
T. E. Hetherington ◽  
R. E. Lombard
Keyword(s):  
Middle Ear ◽  
Particle Motion ◽  
Sound Field ◽  
Underwater Sound ◽  
Resonant Frequencies ◽  
Hearing Sensitivity ◽  
Hearing Thresholds ◽  
Frog Species ◽  
Standing Wave Tube ◽  
Underwater Hearing

A standing wave tube apparatus was used to determine the biophysical basis of underwater hearing sensitivity in 3 species of Rana and in Xenopus laevis. A speaker inside the base of a vertical, water-filled 3 m steel pipe produced standing waves. Pressure and particle motion were measured with a hydrophone and geophone respectively and were spatially 90 degrees out of phase along the length of the tube. Microphonic responses were recorded from the inner ear of frogs lowered through pressure and particle motion maxima and minima. The air-filled lungs of whole frogs produced distortions of the sound field. Preparations of heads with only an air-filled middle ear produced little distortion and showed clear pressure tracking at sound intensities 10-20 dB above hearing thresholds from 200-3000 Hz. Filling the middle ear with water decreased or abolished microphonic responses. Severing the stapes reduced responses except at certain frequencies below about 1000 Hz which varied with body size and likely represent resonant frequencies of the middle ear cavity. We conclude that the frog species examined respond to underwater sound pressure from about 200-3000 Hz with the middle ear cavity responsible for pressure transduction.

Sign in / Sign up

Export Citation Format

Share Document