Special Issue "Underwater Acoustics"

A special issue of Acoustics (ISSN 2624-599X).

Deadline for manuscript submissions: 31 July 2022.

Special Issue Editor

Prof. Dr. Juan Antonio Martínez Mora
E-Mail Website
Guest Editor
Institut d’Investigació per a la Gestió Integrada de les Zones Costaneres (IGIC), Universitat Politècnica de València (UPV), 46730 Gandia, València, Spain
Interests: underwater acoustics; acoustics and acoustics engineering; transducers; ultrasonic and astrophysics

Special Issue Information

Dear Colleagues,

The seas and the oceans are a big reservoir of natural resources and regulate the Earth’s climate system, playing a fundamental role in global temperature warming. Therefore, the study of the ocean is one of the most important challenges facing society today, and one that must be addressed using both fundamental science and engineering. Its study is multidisciplinary, and underwater acoustics is one of the fundamental tools. As electromagnetic waves (attenuated near 100 m) propagate poorly, acoustics waves are the only type of radiation that can propagate at large distances (thousands of kilometres).

Underwater acoustics is closely related to several other fields of acoustic study, including sonar, transduction, acoustic signal processing, underwater communications systems and networks, acoustical oceanography, bioacoustics, and physical acoustics.

Underwater sound is used as a tool to aid the study of marine life, from microplankton to the cetacean or dolphins. Echo sounders are often used to provide data on marine life abundance, distribution, and behavior information, also used for fish location, quantity, size, and biomass estimation.

A topic related with astroparticle physics is proposed in this Special Issue: Acoustics in the Neutrino Telescope, which is a big detector under sea that uses string lines where optical modules (DOM) are installed to detect neutrinos. To reconstruct the neutrino event and the coming direction, it is necessary to monitor the position of each DOM, which is mounted on flexible string lines fixed at the seabed, held close to vertical by buoys and moved by sea currents. Using a piezoceramic transducer, installed inside of each DOM, and some emitters anchored in the sea floor, it is possible to calculate the position of each DOM via a triangulation method. It is thought that ultrahigh energy neutrino interaction in seawater can be detected acoustically.

In recent decades, the advances in the theory and applications of communication systems and submarine networks have been enormous in different research fields, such as: climate control, remote control of AUV/ROV and surveillance, communication between human operators, modem communications, disaster detection systems, early warning, search and rescue, etc.

Underwater acoustics is a topic covered by the open review Acoustics, and this Special Issue aims to bring together contributions related to the subject.

The invitation for contributions is addressed at manuscripts in the form of research articles, review articles, and case study investigations that combine theoretical research and applications related to the underwater acoustics. Moreover, submissions on real applications and simulations in different environments as well as on the effectiveness of the applications are strongly invited in this Special Issue.

Prof. Dr. Juan Antonio Martínez Mora
Guest Editor

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 papers will be 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. Acoustics is an international peer-reviewed open access quarterly 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 1200 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

  • Instrumentation for underwater acoustics applications
  • Acoustics applications for (and from) underwater vehicles (AUV, ROV, etc.)
  • Sonar applications for sea floor exploration and mapping
  • Monitoring cetacean, fishes, and bioacoustical studies in general
  • Underwater applications of acoustics in oceanology, fisheries, and aquaculture
  • Underwater acoustic positioning and navigation
  • Acoustics in underwater Neutrino Telescopes and cabled observatories
  • Underwater acoustics in communication systems and networks

Published Papers (6 papers)

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Research

Article
Underwater Target Localization Using Opportunistic Ship Noise Recorded on a Compact Hydrophone Array
Acoustics 2021, 3(4), 611-629; https://doi.org/10.3390/acoustics3040039 - 08 Oct 2021
Viewed by 403
Abstract
In this research, a new application using broadband ship noise as a source-of-opportunity to estimate the scattering field from the underwater targets is reported. For this purpose, a field trial was conducted in collaboration with JASCO Applied Sciences at Duncan’s Cove, Canada in [...] Read more.
In this research, a new application using broadband ship noise as a source-of-opportunity to estimate the scattering field from the underwater targets is reported. For this purpose, a field trial was conducted in collaboration with JASCO Applied Sciences at Duncan’s Cove, Canada in September 2020. A hydrophone array was deployed in the outbound shipping lane at a depth of approximately 71 m to collect broadband noise data from different ship types and effectively localize the underwater targets. In this experiment, a target was installed at a distance (93 m) from the hydrophone array at a depth of 25 m. In this study, a matched field processing (MFP) algorithm is utilized for localization. Different propagation models are presented using Green’s function to generate the replica signal; this includes normal modes in a shallow water waveguide, the Lloyd-mirror pattern for deep water, as well as the image model. We use the MFP algorithm with different types of underwater environment models and a proposed estimator to find the best match between the received signal and the replica signal. Finally, by applying the scatter function on the proposed multi-channel cross correlation coefficient time-frequency localization algorithm, the location of target is detected. Full article
(This article belongs to the Special Issue Underwater Acoustics)
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Article
Active Control of Submerged Systems by Moving Mass
Acoustics 2021, 3(1), 42-57; https://doi.org/10.3390/acoustics3010005 - 13 Jan 2021
Cited by 1 | Viewed by 1104
Abstract
In this study, the active vibration control of a rectangular plate submerged in water was investigated. Mass dampers were attached to the plate, and the system was modeled via assumed mode. Water is modeled as an inviscid fluid with moving boundaries at fluid–solid [...] Read more.
In this study, the active vibration control of a rectangular plate submerged in water was investigated. Mass dampers were attached to the plate, and the system was modeled via assumed mode. Water is modeled as an inviscid fluid with moving boundaries at fluid–solid interaction surfaces and applied forces on the plate being calculated by Bernoulli equation. The natural frequencies of the plate in vacuum and in water (for partial and fully submerged cases) found from numerical calculations are compared with experimental results to prove the accuracy of the model. Subsequently, for frequency computations, particular frequencies were chosen and active damping was applied for them. To actively control the plate’s vibration by a moving mass with static stable methods, the displacement data of some points were used as input. First, to increase the damping of target mode at low-frequency, the negative acceleration feedback control algorithm in modal-space was applied. Then, the decentralized method was examined. Both methods were successful in suppressing vibration of the submerged rectangular plate. Full article
(This article belongs to the Special Issue Underwater Acoustics)
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Article
Application of Waveguide Invariant Theory to Analysis of Interference Phenomenon in Deep Ocean
Acoustics 2020, 2(3), 595-604; https://doi.org/10.3390/acoustics2030031 - 06 Aug 2020
Cited by 1 | Viewed by 1221
Abstract
When a hydrophone is deployed under the critical depth in deep ocean, the interference pattern will be complex and variable. The waveguide invariant is no longer constant and is treated as a distribution. The interference pattern is impacted by refracted and surface reflected [...] Read more.
When a hydrophone is deployed under the critical depth in deep ocean, the interference pattern will be complex and variable. The waveguide invariant is no longer constant and is treated as a distribution. The interference pattern is impacted by refracted and surface reflected (RSR) modes, as well as surface reflected and bottom reflected (SRBR) modes together. This phenomenon is illustrated by numerical simulation and explained by the waveguide invariant theory in this paper. The theory demonstrates: (1) The interference pattern in zone-b corresponds to the waveguide invariant βRSR that varies quickly and leads to the slope change, which is contributed by RSR modes whose phase velocity is less than the sound velocity at seafloor; (2) The interference pattern in zone-a1 and zone-c1 is corresponding to the βSRBRWS that is the approximately 0.7 and leads to the stable slope, which is contributed by SRBR modes whose phase velocity is between the sound velocity at seafloor and sediment velocity; (3) The interference pattern in zone-a2 and zone-c2 is corresponding to the βSRBRSH which hardly varies at low frequency but varies fiercely with source frequency increasing, so the striations are complex with high frequency, which is contributed by SRBR modes whose phase speed is between sediment speed and half space speed. Full article
(This article belongs to the Special Issue Underwater Acoustics)
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Article
The Use of Soundscapes to Monitor Fish Communities: Meaningful Graphical Representations Differ with Acoustic Environment
Acoustics 2020, 2(2), 382-398; https://doi.org/10.3390/acoustics2020022 - 13 Jun 2020
Cited by 1 | Viewed by 1399
Abstract
Many marine animals produce sounds in several phases of their life cycles, either actively or as a byproduct of their activities, such as during mate attraction or when moving. Recent studies of underwater soundscapes have proved passive acoustic monitoring to be a cost-effective, [...] Read more.
Many marine animals produce sounds in several phases of their life cycles, either actively or as a byproduct of their activities, such as during mate attraction or when moving. Recent studies of underwater soundscapes have proved passive acoustic monitoring to be a cost-effective, non-invasive tool to understand ecological processes, especially when sampling in adverse conditions or at great depth. Four days of sound recordings at three seamounts from the Azorean archipelago were examined to assess the suitability of different sound graphical representations to characterize different acoustic environments that contrast in the contribution of vocal fish communities. Long-term spectrograms, sound pressure level, spectral probability densities and the Acoustic Complexity Index (ACI) were computed for two shallow seamounts (Formigas and Princesa Alice, c. 35 m) and one deep seamount (Condor, 190 m) using graphics with different time spans. Only in Formigas, which presented the highest occurrence of fish sounds, was it possible to observe temporal patterns of fish vocal activity in the graphical representations. We highlight that habitats with a higher diversity and abundance of sounds are the most suitable targets for these methods, while in locations with a low prevalence of fish sounds a combination of several methods would be recommended. Full article
(This article belongs to the Special Issue Underwater Acoustics)
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Communication
A Comparison of Optimal SONAR Array Amplitude Shading Coefficients
Acoustics 2019, 1(4), 808-815; https://doi.org/10.3390/acoustics1040047 - 02 Oct 2019
Viewed by 1630
Abstract
This paper compares two different approaches to deriving shading coefficients (weights) for optimal first order and second order directional sensors (that is; sonobuoys, vectors and dyadic sensors). The first approach is an analytical or a physics-based derivation, involving computations with gradients and linearized [...] Read more.
This paper compares two different approaches to deriving shading coefficients (weights) for optimal first order and second order directional sensors (that is; sonobuoys, vectors and dyadic sensors). The first approach is an analytical or a physics-based derivation, involving computations with gradients and linearized momentum; the second is an adaptive minimum variance distortionless response (MVDR) derivation, which finds weights that minimize the cross spectral density (CSD) matrix. The two approaches are shown to be equivalent. In other words, the adaptive MVDR processing procedure does indeed converge to a physics-based solution, without any pre-existing physical knowledge of the behavior of the acoustic field. This suggests that adaptive algorithms innately seek physics-based solutions when these solutions are optimum. The intent of this short communication is not to advocate for one type of adaptive processing method over another. The observation that is presented here is important though, it confirms that at least in an idealized noise field, adaptive processing converges on an optimal set of shading coefficients, similarly derived based on well-established physical acoustics. Full article
(This article belongs to the Special Issue Underwater Acoustics)
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Article
Applicability of Acoustic Concentration Measurements in Suspensions of Artificial and Natural Sediments Using an Acoustic Doppler Velocimeter
Acoustics 2019, 1(1), 59-77; https://doi.org/10.3390/acoustics1010006 - 19 Dec 2018
Cited by 5 | Viewed by 1879
Abstract
For the investigation of turbulence and particles, interaction measurement systems are required, which are able to measure velocity and concentration fluctuations simultaneously. Acoustic Doppler Velocimeters (ADV) are widely used for velocity and turbulence measurements in natural and artificial flows. Based on the acoustic [...] Read more.
For the investigation of turbulence and particles, interaction measurement systems are required, which are able to measure velocity and concentration fluctuations simultaneously. Acoustic Doppler Velocimeters (ADV) are widely used for velocity and turbulence measurements in natural and artificial flows. Based on the acoustic sonar theory, a model is presented that correlates the ADV’s Signal-to-Noise Ratio (SNR) and the suspended solids concentration of several natural (Ems Estuary, Lake Eixendorf, Lake Altmühl) and artificial sediments (Chinafill, quartz powder, bentonite, metakaolin) for the range 0.001 g/L–50 g/L. Within the presented method, the sound absorption in water and on particles is considered in a continuous approach for sampling frequencies up to 100 Hz. The widely-used log-linear relation between the SNR and the concentration, which is only valid for low concentrations, was extended for the high concentration regime. Measurement results show a similar behavior of the SNR with respect to varying suspended solid concentrations for different sediments. However, the analysis of the fit parameters shows systematic differences depending on the type of sediment. It is concluded that the proposed model is applicable as well for laboratory use as for measurements in rivers and estuaries. Finally, we discuss the reliability of the results and the methodology with regard to measurements in rivers, lakes, and estuaries. Full article
(This article belongs to the Special Issue Underwater Acoustics)
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