References of "Picaut, Judicaël"
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See detailEvaluation des caractéristiques acoustiques d’une rue à partir de mesures
Billon, Alexis ULg; Picaut, Judicaël

in Acoustique & Techniques (2010), 62

The knowledge of acoustic properties of urban surface (absorption, reflection and diffusion coefficients) is very important in the framework of the noise mapping in urban areas. Indeed, most of noise ... [more ▼]

The knowledge of acoustic properties of urban surface (absorption, reflection and diffusion coefficients) is very important in the framework of the noise mapping in urban areas. Indeed, most of noise prediction tools require the use of such coefficients in the boundary equations of the sound propagation models. An indirect method combining experimental data and numerical simulations is then proposed in order to obtain the absorption and scattering coefficients of an urban street. An empirical relationship is first established, linking the scattering variation to an absorption variation. This relation transforms a problem with two variables (absorption and scattering) into a single variable problem (absorption) for a reference scattering coefficient. Secondly, the absorption coefficient is adjusted in order that the numerical results match the experimental data in terms of sound pressure level distribution. Lastly, the obtained value of absorption, associated with the empirical relation, allows to test different absorption and diffusion pairs presenting the same sound level distribution against the experimental reverberation times. Following this procedure, a coefficients pair minimising the discrepancies both on the sound level distribution and the reverberation time is obtained. This method is here applied to a Haussmaniann street. Results show that the obtained absorption coefficients are weak whereas the scattering is quite high, which is physically consistent as the façades are composed of weakly absorbent materials (stone and glass) and fitted with a lot of recesses and protuberances creating scattering. [less ▲]

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See detailAn experimental study of the use of acoustic diffusers to reduce noise in urban areas
Picaut, Judicaël; Hossam Eldien, Hany; Billon, Alexis ULg

Conference (2010, June)

The use of acoustic diffusers to reduce noise in urban areas has been recently numerically investigated [Acta Acustica united with Acustica, Vol. 95 (2009), p. 653–668]. It was shown that a significant ... [more ▼]

The use of acoustic diffusers to reduce noise in urban areas has been recently numerically investigated [Acta Acustica united with Acustica, Vol. 95 (2009), p. 653–668]. It was shown that a significant noise reduction can be observed by considering diffusers on the building façades. In the present study, an experimental investigation is proposed to validate last results. Measurements are carried out using a 1:10 urban street scale model, with and without acoustics diffusers, in order to evaluate the “real” effect of such devices, for several configurations. Results, in terms of sound attenuation and reverberation, show that a positive effect can be observed, provided that diffusers are well designed for the reduction of road traffic noise. [less ▲]

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See detailModélisation des champs sonores en acoustique architecturale par un processus de diffusion
Picaut, Judicaël; Billon, Alexis ULg; Valeau, Vincent et al

Conference (2010, April)

La modélisation des champs sonores en acoustique architecturale est d'autant plus complexe que la géométrie d'étude est elle-même complexe. En particulier, le domaine de propagation peut présenter de ... [more ▼]

La modélisation des champs sonores en acoustique architecturale est d'autant plus complexe que la géométrie d'étude est elle-même complexe. En particulier, le domaine de propagation peut présenter de nombreux volumes couplés de tailles très différentes, connectés par de faibles surfaces de couplage. Dans ces conditions, les formulations analytiques classiques, basées par exemple sur la théorie de la réverbération, ou les méthodes numériques, basées par exemple sur des méthodes de tracé de rayons ou de faisceaux sonores, sont difficilement applicables, voire impossibles. Ces dernières années, une solution alternative, fondée sur l'utilisation d'une équation de diffusion pour la densité d'énergie sonore, a été développée et validée. Dans ce présent travail, nous présentons les développements permettant ainsi de modéliser les champs sonores en acoustique des salles, en prenant en compte les difféerents phénomènes propagatifs mis en jeu, tel que l'atténuation atmosphérique, l'absorption par les parois, la transmission acoustique à travers les cloisons et la réflexion mixte au niveau des surfaces. Dans un second temps, nous présentons la méthode retenue pour la résolution numérique des équations de diffusion mises en jeu. A cet effet, une interface logicielle a été spécialement développée, permettant de manipuler de manière fonctionnelle les données géométriques et acoustiques du problème, avant l'exécution d'un logiciel de calcul multi-physique, en s'affranchissant ainsi du formalisme spécifique associé au modèle de diffusion. Cette interface permet ensuite le post-traitement de l'ensemble des résultats, notamment afin de déterminer et de représenter différents paramètres classiques d'acoustique des salles (niveaux sonores, temps de réverbération. . . ). [less ▲]

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See detailEvaluation des caractéristiques acoustiques d’une rue à partir de mesures
Billon, Alexis ULg; Picaut, Judicaël

Conference (2010, April)

Les caractéristiques acoustiques des rues, tels que les coefficients d’absorption et de diffusion des façades et du sol, sont encore mal connues. En particulier, les façades sont constituées de nombreux ... [more ▼]

Les caractéristiques acoustiques des rues, tels que les coefficients d’absorption et de diffusion des façades et du sol, sont encore mal connues. En particulier, les façades sont constituées de nombreux matériaux différents et peuvent présenter des degrés de relief très variés suivant le style architectural rencontré. Dans cette étude, une méthode est proposée pour obtenir les valeurs de ces coefficients à partir de mesures in situ. Dans un premier temps, une loi empirique liant la variation du coefficient de diffusion à une variation d’absorption en termes de distribution spatiale de l’énergie est recherchée à l’aide d’un logiciel de tir de rayons. Cette loi permet alors de transformer un problème à deux variables (absorption, diffusion) en un problème à une seule variable (absorption équivalente) en fixant la valeur du coefficient d’absorption. Pour chaque bande de fréquence considérée, la valeur d’absorption équivalente minimisant l’erreur commise sur la distribution spatiale de l’énergie par rapport aux mesures est recherchée. Cette valeur associée à la loi empirique précédemment obtenue permet de tester différents couples de valeurs absorption/diffusion en termes de temps de réverbération mesurés. Suivant ce processus, le couple minimisant l’erreur à la fois sur la distribution spatiale de l’énergie et le temps de réverbération est obtenu. Dans cette étude, cette méthode est appliquée à une rue de type Haussmannienne. L’erreur commise est alors de l’ordre de la précision des mesures. De plus, les valeurs obtenues mettent en avant que, pour ce type de rue, la diffusion se produisant aux parois ne peut être négligée. [less ▲]

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See detailSound Field Modeling in Architectural Acoustics using a Diffusion Equation Based Model
Fortin, Nicolas; Picaut, Judicaël; Billon, Alexis ULg et al

Conference (2009, October)

In this paper, an implementation of a model for room-acoustic predictions in COMSOL Multiphysics is presented. The model (called diffusion model) is based on the solving of diffusion equations instead of ... [more ▼]

In this paper, an implementation of a model for room-acoustic predictions in COMSOL Multiphysics is presented. The model (called diffusion model) is based on the solving of diffusion equations instead of classical wave equations and allows simulating the sound propagation in complex geometries at high frequency. Instead of using COMSOL Multiplysics to solve directly the problem, a specific tool has been developed. It is composed of a user-friendly interface (I-Simpa) which manipulates all the physical data of the problem (geometries, acoustic properties and elements…) and generates an interoperability script to execute COMSOL Multiplysics via the generation of .m file scripts. Then, numerical results are processed by I-Simpa for the acoustic post-treatment and results display, like sound levels, reverberation times… [less ▲]

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See detailNumerical simulations of the sound propagation in non rectilinear streets
Billon, Alexis ULg; Picaut, Judicaël; Valeau, Vincent et al

Conference (2009, October)

At high frequencies, the sound propagation can be approximated by the propagation of sound particles which are reflected and absorbed at the boundaries. This propagation follows then a transport process ... [more ▼]

At high frequencies, the sound propagation can be approximated by the propagation of sound particles which are reflected and absorbed at the boundaries. This propagation follows then a transport process. In urban canyons, this transport process can be reduced to a diffusion process. The resultant model allows one to obtain the spatial distribution of the acoustical energy in a street in a few seconds using a classical finite elements program. This diffusion model has been previously validated in rectilinear streets for different geometrical and acoustical parameters. In this paper, more complex geometries such as varying cross-sections, bents and streets crossings are dealt with. As the diffusion model only models the reverberated sound field, diffraction effects on the direct sound field at streets corners are added. The obtained results are then compared to scale model experiments. [less ▲]

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See detailIntroducing atmospheric attenuation within a diffusion model room-acoustic predictions
Billon, Alexis ULg; Picaut, Judicaël; Foy, Cédric et al

in Journal of the Acoustical Society of America (2008), 123(6), 4040-4043

This paper presents an extension of a diffusion model for room acoustics to handle the atmospheric attenuation. This phenomenon is critical at high frequencies and in large rooms to obtain correct ... [more ▼]

This paper presents an extension of a diffusion model for room acoustics to handle the atmospheric attenuation. This phenomenon is critical at high frequencies and in large rooms to obtain correct acoustic predictions. An additional term is introduced in the diffusion equation as well as in the diffusion constant, in order to take the atmospheric attenuation into account. The modified diffusion model is then compared with the statistical theory and a cone-tracing software. Three typical room-acoustic configurations are investigated: a proportionate room, a long room and a flat room. The modified diffusion model agrees well with the statistical theory (when applicable, as in proportionate rooms) and with the cone-tracing software, both in terms of sound pressure levels and reverberation times. [less ▲]

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See detailPrediction of the sound pressure levels using a diffusion model: numerical validations and experimental comparisons
Billon, Alexis ULg; Picaut, Judicaël

in Journal of the Acoustical Society of America (2008), 123(5), 3924-3924

redictions of sound propagation in urban areas have attracted a considerable over the years. If the sound energy is assimilated to particles with a constant energy, their movement can be described by a ... [more ▼]

redictions of sound propagation in urban areas have attracted a considerable over the years. If the sound energy is assimilated to particles with a constant energy, their movement can be described by a transport equation. In canyon streets, this transport equation can be reduced to a diffusion equation whose expression is more simple. In this presentation, sound absorption at the boundaries (buildings facades and ground), as well as atmospheric sound attenuation are introduced. The problem is then solved numerically using a finite elements method for the configuration of a canyon street. A systematic validation of the obtained model is carried out in terms of sound pressure level by comparison to numerical simulations taken from the literature. Comparisons with experimental data are then conducted. Finally, applications in more complex configurations are presented. [less ▲]

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See detailOn the use of diffusion equations to model the acoustics of coupled rooms
Billon, Alexis ULg; Valeau, Vincent; Picaut, Judicaël et al

in Journal of the Acoustical Society of America (2008), 123(5), 3910-3910

he acoustics of coupled rooms are characterized by energy exchanges through apertures and/or partition walls. The use of systems of diffusion equations allows to predict the temporal and spatial energy ... [more ▼]

he acoustics of coupled rooms are characterized by energy exchanges through apertures and/or partition walls. The use of systems of diffusion equations allows to predict the temporal and spatial energy distributions in these configurations quite accurately. In this presentation, the diffusion formalism for room acoustics-prediction is summarized. The systems of equations to be solved in the case of coupling through an aperture and through a partition wall are presented. For two rooms coupled through an aperture (two classrooms connected through an open door), the results obtained with the diffusion model are compared to experimental data, in terms of sound pressure levels and sound decays. On the other hand, for the case of two classrooms connected through a partition wall, the diffusion model is compared to experimental data in terms of sound pressure level difference only. Finally, an engineering application is presented in the configuration involving a workroom including multiple sound sources (e.g., machines) connected to offices through open and closed doors. [less ▲]

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See detailPredictions of the reverberation time in high absorbent room using a modified-diffusion model
Billon, Alexis ULg; Picaut, Judicaël; Sakout, Anas

in Applied Acoustics (2008), 69(1), 68-74

A modification of the diffusion model’s boundary condition, based on the Eyring absorption coefficient, to account for high walls absorption is proposed. Numerical comparisons are carried out for three ... [more ▼]

A modification of the diffusion model’s boundary condition, based on the Eyring absorption coefficient, to account for high walls absorption is proposed. Numerical comparisons are carried out for three geometrical configurations (a proportionate room, a corridor and a flat enclosure). Comparisons with the statistical theory and a ray-tracing software show that the modified boundary condition increases the accuracy of the diffusion model in term of reverberation time in all the simulated configurations. An experimental comparison in the case of a non-uniformly absorbent room (a reverberation chamber covered with patches of glass wool) is also carried out. The modified-diffusion model results match well with the ray-tracing ones. Both models are in agreement with the experimental data for most of third octave bands (discrepancy close to or below 10%). However, some discrepancies up to 40% can also be observed in a few octave bands, probably due to experimental considerations and to the modal behaviour of the room at low frequencies. [less ▲]

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See detailModeling the sound transmission coupled through partition walls using a diffusion model
Billon, Alexis ULg; Foy, Cédric; Picaut, Judicaël et al

in Journal of the Acoustical Society of America (2008), 123(6), 4261-4271

In this paper, a modification of the diffusion model for room acoustics is proposed to account for sound transmission between two rooms, a source room and an adjacent room, which are coupled through a ... [more ▼]

In this paper, a modification of the diffusion model for room acoustics is proposed to account for sound transmission between two rooms, a source room and an adjacent room, which are coupled through a partition wall. A system of two diffusion equations, one for each room, together with a set of two boundary conditions, one for the partition wall and one for the other walls of a room, is obtained and numerically solved. The modified diffusion model is validated by numerical comparisons with the statistical theory for several coupled-room configurations by varying the coupling area surface, the absorption coefficient of each room, and the volume of the adjacent room. An experimental comparison is also carried out for two coupled classrooms. The modified diffusion model results agree very well with both the statistical theory and the experimental data. The diffusion model can then be used as an alternative to the statistical theory, especially when the statistical theory is not applicable, that is, when the reverberant sound field is not diffuse. Moreover, the diffusion model allows the prediction of the spatial distribution of sound energy within each coupled room, while the statistical theory gives only one sound level for each room. [less ▲]

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See detailModelling the sound transmission through separation walls using a diffusion model
Billon, Alexis ULg; Foy, Cédric; Valeau, Vincent et al

Conference (2007, September)

The diffusion model has been used successfully to evaluate the acoustic behaviour of a system of coupled rooms connected through a coupling aperture. In this paper, an extension of this model is proposed ... [more ▼]

The diffusion model has been used successfully to evaluate the acoustic behaviour of a system of coupled rooms connected through a coupling aperture. In this paper, an extension of this model is proposed to deal with the propagation of sound energy through a partition wall. The diffusion model can be considered as an extension of the statistical theory to none diffuse sound fields. Numerical comparisons with the statistical theory are then carried out. The following parameters are varied: its transmission loss of the separation wall, its surface, the coupled room’s absorption coefficient and the coupled room’s volume. The agreement between the statistical theory and the diffusion model is very good. [less ▲]

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See detailSound field modeling in architectural acoustics using a diffusion equation
Picaut, Judicaël; Valeau, Vincent; Billon, Alexis ULg et al

Conference (2006, December)

A numerical approach is proposed to model the reverberated sound field in rooms. The model is based on the numerical implementation of a diffusion model enabling spatial variations of the sound energy ... [more ▼]

A numerical approach is proposed to model the reverberated sound field in rooms. The model is based on the numerical implementation of a diffusion model enabling spatial variations of the sound energy within a room, unlike the statistical theory. The proposed method allows to take into account most of complex phenomena encountered in room acoustics, like mixed reflections on walls (diffuse and specular), low and high absorption on walls, atmospheric attenuation, fitted zones. Moreover, the model can be applied to complex geometries, like multiple coupled rooms of different sizes. In this paper, the model and its numerical implementation are first detailed. Then, an application is proposed for a complex geometry defined by multiple coupled rooms with fitting objects, including low and high absorption on walls, in terms of sound level and reverberation times. The main interest of the model is that such approach requires less computational time in comparison with common approaches like ray-tracing simulations. [less ▲]

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See detailPrediction of the acoustics of coupled rooms with the acoustic-diffusion model
Valeau, Vincent; Billon, Alexis ULg; Hodgson, Murray et al

Conference (2006, June)

A general model is proposed to simulate the acoustics of coupled rooms. It is based on a diffusion equation, solved numerically to perform acoustic predictions. The presence of scattering objects –or the ... [more ▼]

A general model is proposed to simulate the acoustics of coupled rooms. It is based on a diffusion equation, solved numerically to perform acoustic predictions. The presence of scattering objects –or the “fittings”– is also taken into account. Distinct sub-volumes can be defined, representing either coupled volumes or zones with different fitting characteristics. Some sample results are presented, and compared with ray-tracing results and experimental data. Two situations are assessed: two coupled classrooms, and a room divided into two zones, one empty, one fitted. The diffusion-model predictions match the other data satisfactorily, both in terms of sound attenuation and sound decay. Diffusion-based results are obtained with the advantage of low computational time compared to ray-tracing results. [less ▲]

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See detailDifférentes estimations du libre parcours moyen en acoustique des salles : influence sur l’estimation de l’énergie acoustique par un modèle de diffusion
Foy, Cédric; Billon, Alexis ULg; Valeau, Vincent et al

Conference (2006, April)

La plupart des outils de prévision en acoustique des salles sont basés sur le principe du tir de rayons. La précision des résultats dépend alors du nombre de rayons choisi, nécessairement important quand ... [more ▼]

La plupart des outils de prévision en acoustique des salles sont basés sur le principe du tir de rayons. La précision des résultats dépend alors du nombre de rayons choisi, nécessairement important quand la géométrie simulée est grande et/ou disproportionnée, ce qui implique alors des temps de calcul élevés. Pour ce type de géométrie, une méthode alternative, basée sur la résolution numérique d’une équation de diffusion, permet en revanche de réaliser des prévisions acoustiques au prix d’un coût numérique modeste. Ce modèle repose en particulier sur un coefficient de diffusion caractérisant la pièce. Ce coefficient est théoriquement proportionnel au libre parcours moyen (LPM) du local considéré, vérifiant classiquement l’expression 4V/S (V étant le volume de la salle, S la surface des parois). Il est souvent admis que cette valeur est valide pour une salle de dimensions homogènes et dans le cas d’un champ réverbéré diffus. Néanmoins, dans la présente étude nous montrons que pour des locaux particulièrement allongés ou plats, l’atténuation sonore, directement dépendante du coefficient de diffusion, est surestimée par ce modèle. Il en est de même pour des locaux dont la loi de réflexion aux parois s’écarte d’une loi de Lambert. Ainsi, afin d’améliorer les performances du modèle de diffusion, la solution envisagée consiste d’une part, à réaliser un calcul numérique préliminaire du LPM et d’autre part, à considérer les approches analytiques alternatives du LPM rencontrées dans la littérature. La méthode numérique retenue est basée sur le suivi de particules sonores, et permet d’établir le LPM à partir de l’ensemble des distances de collision entre deux parois, pour des conditions de réflexion quelconques. Les résultats de ces approches analytiques et numériques sont présentés en terme d’atténuation sonore pour un local plat et un local allongé, et sont comparés à ceux issus d’autres méthodes numériques. [less ▲]

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See detailValidation expérimentale d’un modèle de diffusion pour l’acoustique des locaux couplés
Billon, Alexis ULg; Picaut, Judicaël; Valeau, Vincent et al

Conference (2006, April)

La modélisation du champ sonore au sein de locaux couplés acoustiquement au moyen d’ouvertures a déjà fait l’objet de nombreuses études. Néanmoins, des modèles à la fois rapides et précis restent encore à ... [more ▼]

La modélisation du champ sonore au sein de locaux couplés acoustiquement au moyen d’ouvertures a déjà fait l’objet de nombreuses études. Néanmoins, des modèles à la fois rapides et précis restent encore à développer, parti-culièrement dans le cas où trois ou quatre salles sont associées. Récemment, un modèle basé sur une équation de diffusion a été appliqué avec succès pour la prévision du champ sonore réverbéré au sein d’un ensemble de deux locaux couplés. Dans cette étude, l’équation de diffusion est résolue numériquement en trois dimensions à l’aide d’une méthode par éléments finis. Cette résolution permet ainsi d’obtenir le niveau et la décroissance sonore en tout point du domaine considéré, au prix d’un faible temps de calcul (quelques minutes). Dans cette étude, les résultats obtenus sont validés, à la fois en termes de niveau du champ sonore et temps de réverbération, à l’aide d’une campagne expérimentale menée dans deux salles de cours couplées entre elles. De plus, une comparaison est réalisée avec des résultats issus de la théorie statistique classique et d’un logi-ciel commercial de tir de rayons largement répandu. Les résultats obtenus montrent un bon accord entre le modèle de diffusion et les expériences. En revanche, la théorie stati-stique ne permet pas de rendre compte précisément de la distribution spatiale et de la décroissance de l’énergie sonore. Enfin, le gain de temps par rapport au logiciel de tir de rayons est très important. [less ▲]

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See detailOn the use of a diffusion model for acoustically coupled rooms
Billon, Alexis ULg; Valeau, Vincent; Sakout, Anas et al

in Journal of the Acoustical Society of America (2006), 120(4), 2043-2054

A numerical model is proposed to predict the reverberant sound field in a system of two coupled volumes that are connected through an open aperture. The model is based on the numerical implementation of a ... [more ▼]

A numerical model is proposed to predict the reverberant sound field in a system of two coupled volumes that are connected through an open aperture. The model is based on the numerical implementation of a diffusion model that has already been applied to predict the sound-energy distribution and the sound decay in single rooms. In comparison with the statistical theory, the proposed approach permits the prediction of the sound field by taking into account the sound source location and the receiver locations as well as the transition from one room to the other at the coupling aperture. Moreover, the diffusion model results match satisfactorily the experimental data in terms of sound-pressure level and reverberation times, both in the room containing the source and in the receiving room. Simulations with a ray-based model are also carried out, leading to results similar to those of the diffusion model, but at a cost of larger computation times. [less ▲]

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See detailValidation of a numerical diffusion equation-based modelling of the reverberated sound field in long rooms
Foy, Cédric; Billon, Alexis ULg; Valeau, Vincent et al

Conference (2005, July)

Many applications as corridors, railways tunnels or tube stations present a long room geometry. A fast and reliable modelling of such sound fields could be helpful for designers. In fact, the classical ... [more ▼]

Many applications as corridors, railways tunnels or tube stations present a long room geometry. A fast and reliable modelling of such sound fields could be helpful for designers. In fact, the classical statistical theory based on the assumptions of diffuse sound field is not applicable in such cases because the reverberant sound energy along the room is not uniform. In this study, several models assuming diffuse reflections of sound by walls are used for predicting the reverberant sound field in long rooms. Two models based on a diffusion equation for the energy density (one numerical and one analytical based on an image approach for describing the sound reflection at the corridor extremity) are compared with a radiosity model, and with a ray tracing software. Predictions are compared in terms of sound attenuation and reverberation time with measured data. The long rooms considered in this study were two rectangular corridors of lengths 20.3m and 47.3m. All models overestimate the attenuation, reaching 6dB for the numerical diffusion based model. When a part of specular reflection (30%) is added in the ray tracing model, the predicted sound attenuation matches with the measured one: even in case of rough surfaces, specular reflections cannot be totally excluded. For reverberation time, the agreement between predictions and experiments is good with fewer than 15% of discrepancy. The best predictions of the reverberation time were given by the diffusion models, with discrepancy less than 2% for the numerical model. So, it could be concluded that it is difficult to find a prediction method which is consistent both in terms of steady state and sound decay for the acoustics of long halls. [less ▲]

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See detailExperimental validation of a diffusion equation-based modeling of the sound field in coupled rooms
Billon, Alexis ULg; Valeau, Vincent; Picaut, Judicaël et al

in Journal of the Acoustical Society of America (2005, April), 117(4), 2581-2581

Sound modeling in coupled rooms (i.e., two acoustically coupled rooms separated by an open area) has attracted considerable attention in the past. However accurate and operational models are still needed ... [more ▼]

Sound modeling in coupled rooms (i.e., two acoustically coupled rooms separated by an open area) has attracted considerable attention in the past. However accurate and operational models are still needed, principally when three or more rooms are coupled. In recent papers, a diffusion equation-based model has been applied to unusual room shapes. For the coupled rooms geometry, this diffusion model has been validated successfully by comparison with the classical statistical theory in a parametrical study of the coupling parameters [Billon et al., J. Acoust. Soc. Am. 116, 2553 (2004)]. In the present work, the diffusion model results are validated by means of a comparison with experimental results, both in terms of sound attenuation and reverberation time. A comparison is also provided with results given by the statistical theory and a ray tracing program. For this purpose, experiments have been conducted in two coupled classrooms with two different sound source locations. The results show a very good agreement between the diffusion model and the experiments. Conversely, the statistical model is not valid for modeling accurately the sound field distribution and decay in both coupled rooms. At last, the diffusion model runs much faster than the ray tracing program. [less ▲]

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See detailReverberated sound field modeling in coupled rooms using a diffusion equation
Billon, Alexis ULg; Valeau, Vincent; Sakout, Anas et al

in Journal of the Acoustical Society of America (2004, October), 116(4), 2553-2553

Sound modeling in coupled rooms has attracted considerable attention in the past, but accurate and operational models are still needed. In recent papers, a diffusion equation based model has been applied ... [more ▼]

Sound modeling in coupled rooms has attracted considerable attention in the past, but accurate and operational models are still needed. In recent papers, a diffusion equation based model has been applied with success to unusual room shapes. This approach allows nonuniform repartition of energy, and is especially relevant in room acoustics for long rooms or complex spaces such as networks of rooms. The present work aims at validating the behavior of the diffusion model in the case of two acoustically coupled rooms separated by an open area. In this purpose, the time-dependent diffusion equation is solved in three dimensions using a finite-element solver. It allows one to predict both sound attenuation and reverberation time at any point of the coupled rooms. Parameters influencing the coupling, i.e., room relative sizes, aperture size and room absorption areas, are investigated. Results are then compared with the classical statistical theory of coupled rooms. Finally, a comparison with experimental data in two coupled classrooms is also provided. [less ▲]

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