Direct and Inverse Problems of Sound Scattering and Propagation in Underwater Acoustics

A special issue of Journal of Marine Science and Engineering (ISSN 2077-1312). This special issue belongs to the section "Physical Oceanography".

Deadline for manuscript submissions: closed (28 February 2024) | Viewed by 6660

Special Issue Editors


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V.I. Il'ichev Pacific Oceanological Institute, Far Eastern Branch Russian Academy of Sciences, 690041 Vladivostok, Russia
Interests: wave propagation; underwater acoustics; numerical simulation of waves in complex media; mathematical physics; asymptotic methods
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Department of Marine Geosciences, School of Marine Science, University of Haifa, Haifa, Israel
Interests: wave propagation theory; ocean acoustics; acoustical oceanography
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Guest Editor
Institute of Acoustics, Chinese Academy of Sciences, Beijing, China
Interests: wave propagation theory; geo-acoustic inversion; ocean tomography; ambient noise
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Special Issue Information

Dear Colleagues,

This Special Issue aims to collect papers in the field of underwater acoustics that are presented at the Underwater Acoustics Conference and Exhibition 2023 (Kalamata, Greece). However, other authors working in this field are also welcome to submit their research. We particularly encourage submissions relating to theoretical and computational aspects of underwater acoustics in a very broad sense, including (but not limited to) mathematical approaches to underwater sound propagation, theoretical analysis of various physical phenomena (including 3D effects), as well as various techniques and approaches to the solution of inverse problems (e.g., geoacoustic inversion, ranging, and tomography methods).

As Guest Editors, we are committed to the fast-track peer-review of high-quality papers reporting new achievements in underwater acoustics and to arranging a collection of research items covering various aspects of the field of research.

Dr. Pavel Petrov
Prof. Dr. Boris Katsnelson
Prof. Dr. Zhenglin Li
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Journal of Marine Science and Engineering is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • underwater acoustics
  • sound propagation
  • 3D modelling
  • horizontal refraction
  • parabolic equation
  • normal modes
  • geoacostic inversion
  • acoustic tomography
  • underwater sound channel
  • geometric acoustics (GA)

Published Papers (6 papers)

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Research

19 pages, 2326 KiB  
Article
Asymptotic Ray Method for the Double Square Root Equation
by Nikolay N. Shilov and Anton A. Duchkov
J. Mar. Sci. Eng. 2024, 12(4), 636; https://doi.org/10.3390/jmse12040636 - 9 Apr 2024
Viewed by 535
Abstract
The parabolic wave equation describes wave propagation in a preferable direction, which is usually horizontal in underwater acoustics and vertical in seismic applications. For dense receiver arrays (receiver spacing is less than signal wavelength), this equation can be used for propagating the recorded [...] Read more.
The parabolic wave equation describes wave propagation in a preferable direction, which is usually horizontal in underwater acoustics and vertical in seismic applications. For dense receiver arrays (receiver spacing is less than signal wavelength), this equation can be used for propagating the recorded wavefield back into the medium for imaging sources and scattering objects. Similarly, for multiple source and receiver array acquisition, typical for seismic exploration and potentially beneficial for ocean acoustics, one can model data in one run using an extension of the parabolic equation—the pseudo-differential Double Square Root (DSR) equation. This extended equation allows for the modeling and imaging of multi-source data but operates in higher-dimensional space (source, receiver coordinates, and time), which makes its numerical computation time-consuming. In this paper, we apply a faster ray method for solving the DSR equation. We develop algorithms for both kinematic and dynamic ray tracing applicable to either data modeling or true-amplitude recovery. Our results can be used per se or as a basis for the future development of more elaborated asymptotic techniques that provide accurate and computationally feasible results. Full article
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16 pages, 4606 KiB  
Article
Bottom Multi-Parameter Bayesian Inversion Based on an Acoustic Backscattering Model
by Yi Zheng, Shengqi Yu, Zhiliang Qin, Xueqin Liu, Chuang Xie, Mengting Liu and Jixiang Zhao
J. Mar. Sci. Eng. 2024, 12(4), 629; https://doi.org/10.3390/jmse12040629 - 8 Apr 2024
Viewed by 789
Abstract
The geoacoustic and physical properties of the bottom, as well as spatial distribution, are crucial factors in analyzing the underwater acoustic field structure and establishing a geoacoustic model. Acoustic inversion has been widely used as an economical and effective method to obtain multi-parameters [...] Read more.
The geoacoustic and physical properties of the bottom, as well as spatial distribution, are crucial factors in analyzing the underwater acoustic field structure and establishing a geoacoustic model. Acoustic inversion has been widely used as an economical and effective method to obtain multi-parameters of the bottom. Compared with traditional inversion methods based on acoustic propagation models, acoustic backscattering models are more suitable for multi-parameter inversion, because they contain more bottom information. In this study, a Bayesian inversion method based on an acoustic backscattering model is proposed to obtain bottom multi-parameters, including geoacoustic parameters (the sound speed and loss parameter), partial physical parameters of the sediment, and statistical parameters of the seafloor roughness and sediment heterogeneity. The bottom was viewed as a kind of fluid medium. A high-frequency backscattering model based on fluid theory was adopted as the forward model to fit the scattering strength between the model prediction and the measured data. The Bayesian inversion method was used to obtain the posterior probability density (PPD) of the inversion parameters. Parameter estimation, uncertainty, and correlation were acquired by calculating the maximum a posterior (MAP), the mean values, the one-dimensional marginal distributions of the PPD, and the covariance matrix. Finally, the high-frequency bottom backscattering strength from the Quinault Range site was employed for inversion tests. The estimated values and uncertainties of various bottom parameters are presented and compared with the directly measured bottom parameters. The comparison results demonstrate that the method proposed herein can be used to estimate the sediment/water sound speed ratio, the sediment/water density ratio, and the spectral exponent of the roughness spectrum effectively and reliably. Full article
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17 pages, 2987 KiB  
Article
Three-Dimensional Modeling of Sound Field Holograms of a Moving Source in the Presence of Internal Waves Causing Horizontal Refraction
by Sergey Pereselkov, Venedikt Kuz’kin, Matthias Ehrhardt, Sergey Tkachenko, Pavel Rybyanets and Nikolay Ladykin
J. Mar. Sci. Eng. 2023, 11(10), 1922; https://doi.org/10.3390/jmse11101922 - 5 Oct 2023
Cited by 3 | Viewed by 973
Abstract
In this paper, we study the variations of holograms of a moving source in an inhomogeneous ocean waveguide. It is assumed that intense internal waves (internal solitons) are the reason for the inhomogeneities of the shallow water waveguide. The results of 3D modeling [...] Read more.
In this paper, we study the variations of holograms of a moving source in an inhomogeneous ocean waveguide. It is assumed that intense internal waves (internal solitons) are the reason for the inhomogeneities of the shallow water waveguide. The results of 3D modeling of the sound field considering horizontal refraction by internal waves are presented. In the context of 3D modeling, the interferogram (sound intensity distributions in frequency–time coordinates) and hologram (2D Fourier transform of the interferogram) of moving sources are analyzed. The hologram consists of two disjoint regions corresponding to the unperturbed field and the field perturbed by internal waves. This structure of the hologram allows for the reconstruction of the interferogram of the unperturbed field in a waveguide in the absence of intense internal waves. The error in the reconstruction of the unperturbed interferogram is estimated. Full article
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19 pages, 7297 KiB  
Article
On the Effect of Horizontal Refraction Caused by an Anticyclonic Eddy in the Case of Long-Range Sound Propagation in the Sea of Japan
by Mikhail Sorokin, Pavel Petrov, Maxim Budyansky, Pavel Fayman, Aleksandr Didov, Aleksandr Golov and Yuri Morgunov
J. Mar. Sci. Eng. 2023, 11(9), 1737; https://doi.org/10.3390/jmse11091737 - 2 Sep 2023
Viewed by 1026
Abstract
The precision of acoustic ranging and navigation depends on the accuracy of the information about the sound speed field in the area of interest. Large-scale inhomogeneities in the bottom relief and water column can significantly affect the horizontal rays corresponding to vertical modes [...] Read more.
The precision of acoustic ranging and navigation depends on the accuracy of the information about the sound speed field in the area of interest. Large-scale inhomogeneities in the bottom relief and water column can significantly affect the horizontal rays corresponding to vertical modes (in the framework of Burridge–Weinberg formalism), which can lead to delays in the acoustic signal modal components, as compared to propagation along the geodesics on the Earth’s surface. In this study, the influence of horizontal refraction on the delay times of the modal components is considered. In particular, it is studied to what extent the presence of a synoptic eddy near the source–receiver path increases the effective propagation distances due to horizontal refraction. The elongation of horizontal eigenrays relative to the geodesic connecting the source and the receiver is also estimated. The influence of hydrological inhomogeneities on the propagation time of different modal components of a broadband acoustic signal is investigated. This is accomplished by the integration of the group slowness (reciprocal to the group speed) along the horizontal eigenrays connecting the locations of the source and the receiver. Implications for improving the accuracy of the solution of acoustic ranging problems are discussed. Full article
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18 pages, 2085 KiB  
Article
Modulation Effects of Internal-Wave Evolution on Acoustic Modal Intensity Fluctuations in a Shallow-Water Waveguide
by Qinran Li, Chao Sun, Lei Xie and Xiaodong Huang
J. Mar. Sci. Eng. 2023, 11(9), 1686; https://doi.org/10.3390/jmse11091686 - 26 Aug 2023
Cited by 1 | Viewed by 1028
Abstract
Internal solitary waves evolving with time in shallow water are known to affect sound propagation significantly. Unlike prior work studying the acoustic effects of individual internal-wave properties separately, this paper elucidates and evaluates the influence of a complete evolution process of internal waves [...] Read more.
Internal solitary waves evolving with time in shallow water are known to affect sound propagation significantly. Unlike prior work studying the acoustic effects of individual internal-wave properties separately, this paper elucidates and evaluates the influence of a complete evolution process of internal waves on acoustic fields both theoretically and by the coupled ocean-acoustic simulation. Two evolving wave properties considered here are shape deformations including the variations of wave amplitudes and widths and packet dispersion manifested as the increasing wavelength (i.e., the distance between successive solitons). The acoustic modal intensity expressed by the Dyson series solution is reformulated to explicitly reveal the modulation effects induced by the deformation and dispersion of internal waves. Dispersion leads to modal interference and causes the intensity envelope to oscillate with the varying wavelength. Deformation modulates intensity in a non-oscillatory manner that is less predictable due to the complexity of amplitude and width variations. In the environment reconstructed from the field observations of internal waves in the South China Sea, the modal intensity simulated by the parabolic-equation model exhibits pronounced modulation effects, where the modal interference due to dispersion dominates the intensity-envelope shape, and deformation affects the extremum positions of envelopes. Full article
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18 pages, 7303 KiB  
Article
A Novel Finite Difference Scheme for Normal Mode Models in Underwater Acoustics
by Wei Liu, Guojun Xu, Xinghua Cheng and Yongxian Wang
J. Mar. Sci. Eng. 2023, 11(3), 553; https://doi.org/10.3390/jmse11030553 - 4 Mar 2023
Cited by 1 | Viewed by 1583
Abstract
Normal mode models are commonly used to simulate sound propagation problems in horizontally stratified oceanic environments. Although several normal mode models have been developed, the fundamental techniques for accurately and efficiently solving the modal equation are still under development. Since the standard three-point [...] Read more.
Normal mode models are commonly used to simulate sound propagation problems in horizontally stratified oceanic environments. Although several normal mode models have been developed, the fundamental techniques for accurately and efficiently solving the modal equation are still under development. Since the standard three-point central finite difference scheme (SFD) for the modal equation has a relatively large numerical error, at least twenty sampling grid points per wavelength should be set in the depth direction. Herein, a novel finite difference scheme (NFD) is developed to further improve the accuracy of the mode solution, and the resulting linear system still has a tridiagonal structure similar to that of the SFD. To compare the performance of the NFD to that of the SFD, the NFD has been implemented in the open-source normal mode model KrakenC, and three acoustic propagation cases have been carried out, including the plane-wave reflection, the Pekeris waveguide, and the Munk waveguide. Test results show that the NFD presented in this paper is more accurate than the SFD, and can be used to reduce the number of grid points needed in the depth direction for solving the modal equation in normal mode models. Full article
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