The Complete Image-Source Method for the Prediction of Sound Distribution in Non-Diffuse Enclosed Spaces

Dance, Stephen; Shield, Bridget

doi:10.1006/jsvi.1996.0770

Cited by 27 publications

(16 citation statements)

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“…An image method introduced by Gibbs and Jones (1972) was used in this study because its algorithm is easy to implement and the result of the reflection sequence is accurate (Dance and Shield 1997;Lehmann and Johansson 2008). A theoretical model based on the principle of this method was used to explore energy intensity in the 1950s (Bolt et al 1950;Doak 1959).…”

Section: Simulation Settingmentioning

confidence: 99%

Parameter study of sound energy distribution in cuboid extra-large spaces

Wang

Kang

2019

Build. Simul.

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The aim of this paper is to explore the sound energy distribution in cuboid extra-large spaces. The surface absorption and height are studied as the parameters using the image method. Air absorption is also discussed in this paper. The results show that the difficulty of reducing the noise increases with the increasing volume in extra-large spaces. Even if the ratio between the equivalent absorption area and the total surface is kept constant, the efficiency of noise reduction decreases by approximately 21% in this study. The absorption areas on the floor and the walls have a better performance on noise reduction than that on the ceiling. When the initial height of an extra-large space with general ratio of three dimensions is continuously halved, the variation in the noise level is close to a fixed value, and when the initial height continuously doubled, the noise level decreased approximately exponentially. The predicted difference between with and without consideration of air absorption increases linearly with the source-receiver distance.

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Section: Simulation Settingmentioning

confidence: 99%

Parameter study of sound energy distribution in cuboid extra-large spaces

Wang

Kang

2019

Build. Simul.

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“…The energy discontinuity percentage ͑EDP͒, defined by Dance and Shield,11 rather than the number of reflections, is used to decide when to terminate the tracing of a ray. The EDP represents the percentage of a ray's energy lost before the termination of the tracing of the ray.…”

Section: A Energy Discontinuity Percentagementioning

confidence: 99%

The prediction of speech intelligibility in underground stations of rectangular cross section

Yang

Shield

2001

The Journal of the Acoustical Society of America

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Long enclosures are spaces with nondiffuse sound fields, for which the classical theory of acoustics is not appropriate. Thus, the modeling of the sound field in a long enclosure is very different from the prediction of the behavior of sound in a diffuse space. Ray-tracing computer models have been developed for the prediction of the sound field in long enclosures, with particular reference to spaces such as underground stations which are generally long spaces of rectangular or curved cross section. This paper describes the development of a model for use in underground stations of rectangular cross section. The model predicts the sound-pressure level, early decay time, clarity index, and definition at receiver points along the enclosure. The model also calculates the value of the speech transmission index at individual points. Measurements of all parameters have been made in a station of rectangular cross section, and compared with the predicted values. The predictions of all parameters show good agreement with measurements at all frequencies, particularly in the far field of the sound source, and the trends in the behavior of the parameters along the enclosure have been correctly predicted.

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“…The level N of the image sources to be considered in order to get a good estimation of the energies is defined by considering that sources of level higher than N have negligible contributions. The criteria given in reference [24] is expressed in terms of the percentage P of energy which should have been attenuated, the average absorption coefficient at boundaries α, the mean free path of the plates l, and the attenuation coefficient m = ηω/c :…”

Section: The Calculated Systemmentioning

confidence: 99%

Specular and diffuse reflections of rays in coupled thin plates at high frequencies

Cotoni

Bot

2003

Journal of Sound and Vibration

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The flexural energy distribution in two right-angled point-excited thin plates at high frequencies is investigated by means of an integral energy flow approach. Time and frequencyaveraged energy fields are described by the superposition of uncorrelated cylindrical waves stemming from both boundaries and direct sources. Specular and diffuse laws are considered for the reflection and transmission of rays, giving rise to two kinds of energy equations. The diffuse law leads to a Fredholm integral equation while the specular law is shown to allow an image source solution when the plates have identical propagation properties. The algorithm for computing the image position, magnitude and directivities is described. Then, some comparisons between the results from the two energy formulations and also from the Statistical Energy Analysis and the numerical solving of the equations of motion are performed with a couple of damped plates at high frequency. The non diffuse pattern of the averaged flexural energy fields is well described by the energy flow approaches.

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The Complete Image-Source Method for the Prediction of Sound Distribution in Non-Diffuse Enclosed Spaces

Cited by 27 publications

References 0 publications

Parameter study of sound energy distribution in cuboid extra-large spaces

Parameter study of sound energy distribution in cuboid extra-large spaces

The prediction of speech intelligibility in underground stations of rectangular cross section

Specular and diffuse reflections of rays in coupled thin plates at high frequencies

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