Special Issue on Verification and Validation of Airgun Source Signature and Sound Propagation Models

2018 ◽  
Vol 43 (1) ◽  
pp. 280-281
Keyword(s):  
Sound Propagation ◽  
Verification And Validation ◽  
Special Issue ◽  
Propagation Models

Special issue on verification and validation

1999 ◽  
Vol 12 (1-2) ◽  
pp. 1-2 ◽  
Author(s):  
Robert Plant ◽  
Grigoris Antoniou
Keyword(s):  
Verification And Validation ◽  
Special Issue

LATTICE GAS WAVE PROPAGATION MODELS INCLUDING DISSIPATION

1995 ◽  
Vol 03 (01) ◽  
pp. 69-93 ◽  
Author(s):  
YASUSHI SUDO ◽  
VICTOR W. SPARROW
Keyword(s):  
Wave Propagation ◽  
Random Walk ◽  
Diffusion Equation ◽  
Lattice Gas ◽  
Sound Propagation ◽  
Two Dimensional ◽  
Propagation Models ◽  
One Dimensional ◽  
Lattice Gas Models ◽  
Wave Models

New lattice gas models for one-dimensional (1D) and two-dimensional (2D) sound propagation have been recently proposed by the authors. These models were dissipationless and deterministic. In this paper, it will be shown how dissipation effects can be included into these lattice gas wave models. To simulate these dissipation effects, the lattice gas particles are assumed to take a random walk. The resulting models combine the authors' lattice gas wave models with published lattice gas models for the diffusion equation. The formulations are stable and consistent.

scholarly journals Computational aeroacoustics of the EAA benchmark case of an axial fan

Acta Acustica ◽  
2020 ◽  
Vol 4 (5) ◽  
pp. 22
Author(s):  
Stefan Schoder ◽  
Clemens Junger ◽  
Manfred Kaltenbacher
Keyword(s):  
Sound Propagation ◽  
Turbulence Modeling ◽  
Flow Simulation ◽  
Sound Field ◽  
Axial Fan ◽  
Mean Velocity ◽  
Propagation Models ◽  
Term Structures ◽  
Sensor Signals ◽  
Mesh Convergence

This contribution benchmarks the aeroacoustic workflow of the perturbed convective wave equation and the Ffowcs Williams and Hawkings analogy in Farassat’s 1A version for a low-pressure axial fan. Thereby, we focus on the turbulence modeling of the flow simulation and mesh convergence concerning the complete aeroacoustic workflow. During the validation, good agreement has been found with the efficiency, the wall pressure sensor signals, and the mean velocity profiles in the duct. The analysis of the source term structures shows a strong correlation to the sound pressure spectrum. Finally, both acoustic sound propagation models are compared to the measured sound field data.

scholarly journals Improving the Performance of Mode-Based Sound Propagation Models by Using Perturbation Formulae for Eigenvalues and Eigenfunctions

2021 ◽  
Vol 9 (9) ◽  
pp. 934
Author(s):  
Alena Zakharenko ◽  
Mikhail Trofimov ◽  
Pavel Petrov
Keyword(s):  
Sound Propagation ◽  
Underwater Acoustics ◽  
Computational Cost ◽  
Normal Modes ◽  
Sound Field ◽  
Field Calculation ◽  
Combined Model ◽  
Eigenvalues And Eigenfunctions ◽  
Propagation Models ◽  
Area Of Interest

Numerous sound propagation models in underwater acoustics are based on the representation of a sound field in the form of a decomposition over normal modes. In the framework of such models, the calculation of the field in a range-dependent waveguide (as well as in the case of 3D problems) requires the computation of normal modes for every point within the area of interest (that is, for each pair of horizontal coordinates x,y). This procedure is often responsible for the lion’s share of total computational cost of the field simulation. In this study, we present formulae for perturbation of eigenvalues and eigenfunctions of normal modes under the water depth variations in a shallow-water waveguide. These formulae can reduce the total number of mode computation instances required for a field calculation by a factor of 5–10. We also discuss how these formulae can be used in a combination with a wide-angle mode parabolic equation. The accuracy of such combined model is validated in a series of numerical examples.

scholarly journals THREE-DIMENSIONAL SOUND PROPAGATION MODELS USING THE PARABOLIC-EQUATION APPROXIMATION AND THE SPLIT-STEP FOURIER METHOD

2013 ◽  
Vol 21 (01) ◽  
pp. 1250018 ◽  
Author(s):  
YING-TSONG LIN ◽  
TIMOTHY F. DUDA ◽  
ARTHUR E. NEWHALL
Keyword(s):  
Parabolic Equation ◽  
Sound Propagation ◽  
Azimuthal Angle ◽  
Three Dimensional ◽  
Fourier Method ◽  
Radial Coordinate ◽  
Underwater Sound ◽  
Propagation Models ◽  
Cylindrical Grid ◽  
Grid Points

The split-step Fourier method is used in three-dimensional parabolic-equation (PE) models to compute underwater sound propagation in one direction (i.e. forward). The method is implemented in both Cartesian (x, y, z) and cylindrical (r, θ, z) coordinate systems, with forward defined as along x and radial coordinate r, respectively. The Cartesian model has uniform resolution throughout the domain, and has errors that increase with azimuthal angle from the x axis. The cylindrical model has consistent validity in each azimuthal direction, but a fixed cylindrical grid of radials cannot produce uniform resolution. Two different methods to achieve more uniform resolution in the cylindrical PE model are presented. One of the methods is to increase the grid points in azimuth, as a function of r, according to nonaliased sampling theory. The other is to make use of a fixed arc-length grid. In addition, a point-source starter is derived for the three-dimensional Cartesian PE model. Results from idealized seamount and slope calculations are shown to compare and verify the performance of the three methods.

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