A hybrid BIE/FFP scheme for predicting barrier efficiency outdoors

Taherzadeh, Shahram; Li, Kai Ming; Attenborough, Keith

doi:10.1121/1.1381539

Cited by 3 publications

(3 citation statements)

References 36 publications

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“…Q i = Q and θ ij =0, then the double summation in the last term of Equation (13) Figure 1 has already shown that the simplified Equation (10) has good agreement with direct realisations. The agreement between the simplified MCF prediction, Equation (13), and the full MCF method, Equation (12), is even better, as can be seen in Figure 2, which uses the same simulation cases of Figure 1. The scatter of data is much less in Figure 2 because of the deterministic nature of the MCF calculations.…”

Section: Mutual Coherence Function (Mcf)mentioning

confidence: 50%

“…In these works, the boundary element method (BEM) [11] has been shown to be highly effective and accurate for predicting the insertion loss of barriers of complex shapes. BEM schemes that use special formulations of the Green's function to take into account of atmospheric refraction on sound propagation over a barrier have been proposed [12,13]. However almost all studies on complex shaped barriers do not consider the effect of turbulence.…”

Section: Introductionmentioning

confidence: 99%

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A boundary element method for the calculation of noise barrier insertion loss in the presence of atmospheric turbulence

Lam

2004

Applied Acoustics

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Atmospheric turbulence is an important factor that limits the amount of attenuation a barrier can provide in the outdoor environment. It is therefore important to develop a reliable method to predict its effect on barrier performance. The boundary element method (BEM) has been shown to be a very effective technique for predicting barrier insertion loss in the absence of turbulence. This paper develops a simple and efficient modification of the BEM formulation to predict the insertion loss of a barrier in the presence of atmospheric turbulence. The modification is based on two alternative methods: 1) random realisations of log-amplitude and phase fluctuations of boundary sources; and 2) de-correlation of source coherence using the mutual coherence function (MCF). An investigation into the behaviours of these two methods is carried out and simplified forms of the methods developed. Some systematic differences between the predictions from the methods are found. When incorporated into the BEM formulation, the method of random realisations using only phase fluctuations and the method of MCF de-correlation provides predictions that agree well with predictions by the Parabolic Equation method and by the Scattering Cross-Section method on a variety of thin barrier configurations. Surprisingly the turbulence effect predicted by random realisations of both log-amplitude and phase fluctuations are found to be significantly stronger than those -2 -predicted by other methods even for cases well within the saturation limit of the amplitude fluctuation.

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Section: Mutual Coherence Function (Mcf)mentioning

confidence: 50%

Section: Introductionmentioning

confidence: 99%

A boundary element method for the calculation of noise barrier insertion loss in the presence of atmospheric turbulence

Lam

2004

Applied Acoustics

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“…Another extension of the BEM, which accounts for a refracting atmosphere as well as a non-uniform boundary was introduced by Taherzade et al [40].…”

Section: B O U N D a R Y E Lem En T Ivlethodsmentioning

confidence: 99%

A forward-advancing wave expansion method for numerical solution of large-scale sound propagation problems

Rolla

Rice

2006

Journal of Sound and Vibration

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A Short Survey on Green’s Function for Acoustic Problems

Okoyenta

Liu

et al. 2020

J. Theor. Comp. Acout.

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Green’s functions for acoustic problems is the fundamental solution to the inhomogeneous Helmholtz equation for a point source, which satisfies specific boundary conditions. It is very significant for the integral equation and also serves as the impulse response of an acoustic wave equation. They are important for acoustic problems that involve the propagation of sound from the source point to the observer position. Once the Green’s function, which satisfies the necessary boundary conditions, is obtained, the sound pressure at any point away from the source can be easily calculated by the integral equation. The major problem faced by researchers is in the process of constructing these Green’s functions which satisfy a specific boundary condition. The aim of this work is to review some of these fundamental solutions available in the literature for different boundary conditions for the ease of analyzing acoustics problems. The review covers the free-space Green’s functions for stationary source and rotational source, for both when the observer and the acoustic medium are at rest and when the medium is in uniform flow. The half-space Green’s functions are also summarized for both stationary acoustic source and moving acoustic source, derived using the image source method, equivalent source method and complex equivalent method in both time domain and frequency domain. Each of these methods used depends on the different impedance boundary conditions for which the Green’s function will satisfy. Finally, enclosed spaced Green’s functions for both rectangular duct and cylindrical duct for an infinite and finite duct is also covered in the review.

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A hybrid BIE/FFP scheme for predicting barrier efficiency outdoors

Cited by 3 publications

References 36 publications

A boundary element method for the calculation of noise barrier insertion loss in the presence of atmospheric turbulence

A boundary element method for the calculation of noise barrier insertion loss in the presence of atmospheric turbulence

A forward-advancing wave expansion method for numerical solution of large-scale sound propagation problems

A Short Survey on Green’s Function for Acoustic Problems

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