Underwater Broadband Acoustic Scattering Modelling Based on FDTD

Shao, Jie; Zhao, Weiqian; Xiangjun, Jin; Zhang, Xin; Malekian, Reza

doi:10.5755/j01.eee.21.2.11513

Cited by 6 publications

(3 citation statements)

References 11 publications

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“…According to [10]- [12], the avoidance threshold SPL for grey seals is approximately 140 dB. Considering the sound propagation model from [13] as well as real measurements from [12], [14], the sound absorption in seawater can be described using the following approximate formula:…”

Section: Pulse Timingmentioning

confidence: 99%

Design of Acoustic Signals for a Seal Deterrent Device

Āboltiņš

Grizāns

Pikuļins

et al. 2020

Electrical, Control and Communication Engineering

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During the past decade, attacks by grey seals on fishing nets in the Baltic Sea have caused considerable loss of fish catch and damage to fishing gears. One of the approaches to reduce the number of seal attacks on fishing nets is to use acoustic deterrent devices (ADDs). Unfortunately, most of the commercially available ADDs are not well suited to the deployment in the sea and require considerable additional investments. The objective of the present research is to develop a compact and cost-efficient ADD for deployment in the sea environment. This paper is devoted to the design of acoustic signals for a prototype ADD. Signals from other experimental and commercially available ADDs are studied and compared. Moreover, limitations imposed by the underwater environment, transducers, battery power, and fish hearing are analysed and considered during the development of signal patterns. The results of tests conducted in an artificial reservoir and in the sea are presented.

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Section: Pulse Timingmentioning

confidence: 99%

Design of Acoustic Signals for a Seal Deterrent Device

Āboltiņš

Grizāns

Pikuļins

et al. 2020

Electrical, Control and Communication Engineering

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“…A considerable breakthrough has been made in the method of calculating the acoustic scattering of underwater targets, but for the complex structures of underwater vehicles, only numerical calculations or approximate calculations using acoustic scattering can be employed. More complete numerical calculation methods and approximation methods include the finite element method (FEM) and boundary element method (BEM) [11,12], T-matrix method [13][14][15], time domain finite difference method (TDFDM) [16,17], deformation column method (DCM) [18][19][20], and wave superposition method (WSM) [21]. There are many other approximate methods.…”

Section: Introductionmentioning

confidence: 99%

Optimum design of acoustic stealth shape of underwater vehicle model with conning tower

Tang¹,

Wang²,

Miao³

et al. 2023

Front. Phys.

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We present an optimization algorithm for achieving optimal acoustic stealth performance during designing an underwater vehicle shape in the free field using COMSOL-MATLAB integrated software. A component superposition method based on phase interference is adopted to simplify and decompose a nonaxisymmetric complex underwater vehicle model into two main parts: the hull and the conning tower. The shape of underwater vehicle hull is described mathematically with a sequence of undetermined coefficients for optimization. The basic mathematical principle of the proposed method is Kirchhoff approximation, also called planar element method (PEM). Additionally, some examples and experimental results show that this method can realize the automatic optimization design of acoustic stealth shapes for underwater vehicle model in a given frequency band and acoustic incident angle range. The underwater vehicle design has a smooth appearance with low target strength (TS) or angle detection rate for most detection angles and frequency bands after optimized.

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“…Moreira [28] solved the propagation equation of acoustic waves in uniform and inhomogeneous medium using the frequencydomain finite-difference method combined with PML and analyzed the influence of the PML absorption coefficient on the acoustic absorption effect. Jie [29] adopted PML for the broadband scattering model of the underwater target and set different absorption coefficients according to the frequency of the incident wave. It shows that the acoustic absorption effect works well at each frequency.…”

Section: Introductionmentioning

confidence: 99%

Finite-Difference Frequency-Domain Scheme for Sound Scattering by a Vortex with Perfectly Matched Layers

Zhang,

Ling,

et al. 2023

Mathematics

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Understanding the effect of vortexes on sound propagation is of great significance in the field of target detection and acoustic imaging. A prediction algorithm of the two-dimensional vortex scattering is realized based on a finite-difference frequency-domain (FDFD) numerical scheme with perfectly matched layers (PML). Firstly, the governing equation for flow–sound interaction is given based on the perturbation theory, and the FDFD program is built. Subsequently, the mesh independence is verified, and the result has a good convergence when the mesh corresponds to over 15 nodes per wavelength. Then, computational parameters of the PML are discussed to achieve better absorbing boundary conditions. Finally, the results of this algorithm are compared with previous literature data. Results show that for different cortex scattering cases, the absorption coefficient should vary linearly with the density of the medium and the incident wave frequency. When the thickness of the PML boundary is greater than 2.5 times the wavelength, the PML boundary can absorb the scattering sound effectively. This provides a reliable algorithm for the numerical study of the effect of vortexes on sound propagation.

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Underwater Broadband Acoustic Scattering Modelling Based on FDTD

Cited by 6 publications

References 11 publications

Design of Acoustic Signals for a Seal Deterrent Device

Design of Acoustic Signals for a Seal Deterrent Device

Optimum design of acoustic stealth shape of underwater vehicle model with conning tower

Finite-Difference Frequency-Domain Scheme for Sound Scattering by a Vortex with Perfectly Matched Layers

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