Monostatic Versus Bistatic SONAR Evaluation with a Backscattering Acoustic Propagation Model

INCREaSE 2019 ◽  
2019 ◽  
pp. 265-276
Author(s):  
Ashley Payne Hughes ◽  
António João Silva ◽  
Orlando Camargo Rodríguez
Keyword(s):  
Acoustic Propagation ◽  
Propagation Model

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.

Horizontal multipath in transoceanic acoustic propagation: Model results and data.

1991 ◽  
Vol 90 (4) ◽  
pp. 2347-2347
Author(s):  
B. E. McDonald ◽  
W. A. Kuperman ◽  
K. Heaney
Keyword(s):  
Acoustic Propagation ◽  
Propagation Model

Validation of a finite-difference acoustic propagation model of transcranial ultrasound

2012 ◽  
Vol 132 (3) ◽  
pp. 1927-1927
Author(s):  
Guillaume Bouchoux ◽  
Kenneth B. Bader ◽  
Joseph J. Korfhagen ◽  
Jason L. Raymond ◽  
Shivashankar Ravishankar ◽  
...  
Keyword(s):  
Finite Difference ◽  
Acoustic Propagation ◽  
Propagation Model ◽  
Transcranial Ultrasound

Shape optimization of a general bypass duct for tone noise reduction using continuous adjoint method

2013 ◽  
Vol 228 (1) ◽  
pp. 119-134 ◽  
Author(s):  
S Qiu ◽  
WB Song ◽  
H Liu
Keyword(s):  
Shape Optimization ◽  
Design Problem ◽  
Adjoint Method ◽  
Finite Difference Methods ◽  
Acoustic Propagation ◽  
Low Noise ◽  
Design Tool ◽  
Propagation Model ◽  
Adjoint Formulation ◽  
Continuous Adjoint

A novel continuous adjoint-based acoustic propagation method is proposed for low-noise turbofan duct design. A fan bypass duct tonal noise propagation model that is verified by comparison with an analytical solution of the modal radiation from a semi-infinite duct with the shear layer is enhanced with its continuous adjoint formulation, having been applied to design the bypass duct. First, this article presents the complete formulation of the time-dependent optimal design problem. Second, a continuous adjoint-based acoustic propagation method for two-dimensional bypass duct configurations is derived and presented. This article aims at describing the potential of the adjoint technique for aeroacoustic shape optimization. The implementation of the unsteady aeroacoustic adjoint method is validated by comparing the sensitivity derivative with that obtained by finite differences. Using a continuous adjoint formulation, the necessary aerodynamic gradient information is obtained with large computational savings over traditional finite-difference methods. The examples presented demonstrate that the combination of a continuous-adjoint algorithm with a noise prediction method can be an efficient design tool in the bypass duct noise design problem.

Modeled acoustic propagation through a measured large-amplitude nonlinear internal wave in northern South China Sea

2020 ◽  
Author(s):  
Peng Qi
Keyword(s):  
South China Sea ◽  
Internal Waves ◽  
South China ◽  
Large Amplitude ◽  
Sound Propagation ◽  
Transmission Loss ◽  
Northern South China Sea ◽  
Acoustic Propagation ◽  
Propagation Model ◽  
China Sea

<p>Preliminary results are presented from an analysis of modeled mid-frequency sound propagation through a measured large-amplitude nonlinear internal solitary wave, and in-situ measurements of trains of nonlinear internal waves in northern South China Sea (SCS) as well. An acoustic propagation model based on ray theory was utilized to compute the transmission loss (TL) associated with passing the large depression measured internal waves. The TL was computed using the model considering (1) range-dependent and range-independent environmental scenario and (2) for different source and receiver depth configurations. This presentation will propose several interesting aspects of influence of internal waves on acoustic propagation, including "shadow zones", with or without eddy, etc.</p>

scholarly journals Application of the Acoustic Propagation Model to a deep‐water cross‐shelf curtain

2017 ◽  
Vol 8 (10) ◽  
pp. 1305-1308 ◽  
Author(s):  
Charlie Huveneers ◽  
Kilian M. Stehfest ◽  
Colin A. Simpfendorfer ◽  
Jayson Semmens ◽  
Alistair J. Hobday ◽  
...  
Keyword(s):  
Deep Water ◽  
Acoustic Propagation ◽  
Propagation Model

The Influence of Positional Parameters on the Effect of a Noise-Jammer Based on Broadband Acoustic Propagation Model

2013 ◽  
Vol 791-793 ◽  
pp. 2043-2047
Author(s):  
Kang Le Miao ◽  
Ri Jie Yang ◽  
Xiong Xiong ◽  
Jian Hui Han
Keyword(s):  
Normal Mode ◽  
Fourier Transformation ◽  
Accurate Result ◽  
Transmission Loss ◽  
Spherical Wave ◽  
Acoustic Propagation ◽  
Propagation Model ◽  
Discrete Fourier Transformation ◽  
Approximate Evaluation ◽  
Long Time

In a long time, the specialists in underwater acoustic countermeasure field were used to get an approximate evaluation of the transmission loss of noise signals by spreading loss equation of spherical wave, which led to results with a low accurateness. Based on normal mode theories and discrete Fourier transformation (DFT), derived the composition and process of the broadband acoustic propagation model. Then the transmission loss could be calculated via this propagation model, which could get a relatively more accurate result. The influence of three key positional parameters, the orientation, distance and depth of the noise-jammer were studied in this paper. The method and conclusions in this paper can provide a reliable foundation for tactical research on noise-jammers.

Measurement of atmospheric sound propagation and meteorological parameters to support development of an acoustic propagation model

2016 ◽  
Vol 140 (4) ◽  
pp. 3260-3260
Author(s):  
Melissa A. Hall ◽  
Teresa Ryan ◽  
Seth Hubbard ◽  
Joseph F. Vignola ◽  
John A. Judge ◽  
...  
Keyword(s):  
Meteorological Parameters ◽  
Sound Propagation ◽  
Acoustic Propagation ◽  
Propagation Model
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