Modélisation numérique pour l'acoustique environnementale : simulation de champs météorologiques et intégration dans un modèle de propagation

Abstract : Actually, it exists a major societal issue to be interested in outdoor sound propagation and specially, in our context, to reduce the uncertainty in noise levels estimation and thus to improve the analyses accuracy, from engineers to research institutes. The influence of meteorology on outdoor sound propagation is significant. It is therefore necessary to understand and quantify the micro scales phenomena into the atmospheric boundary layer. In this way, the French research meteorological model (Meso-NH) has been used. After comparing results of this model at very fine resolution (~1 meter) to measurements issued from the databases of two experimental campaigns (Lannemezan 2005 and Long Term Monitoring Station: LTMS), it appeared necessary to develop this tool in order to take into account the drag force of the trees. Finally, the Meso-NH results for the wind, temperature and turbulent kinetic energy fields are satisfactory. Then, theses informations can be used as input data for acoustic models. Our time domain acoustic model is based on Transmission Line Matrix method (TLM). Its development was done in order to be applied to outdoor sound propagation: taking into account topography, soil types, meteorological conditions, etc. The numerical validation of the TLM method, by comparison with other models (analytical and numerical: Parabolic Equation), has shown the relevance of its use in the context of environmental acoustics. Finally, thanks to these models, simulated noise levels in different propagation conditions (downward, upward and homogeneous refraction conditions) were compared to in situ measurements carried out during the Lannemezan 2005 experimental campaign. Satisfying results were obtained regarding the observed phenomena variability. However, using the micro-meteorological model Meso-NH is difficult because of the strong acoustic sensitivity to the vertical celerity profiles. A feasibility study on a more complex experience (LTMS) is encouraging and, provided having substantial computing resources, it permits to consider the TLM as an accurate method in the context of environmental acoustics.
Mots-clés : ACOUSTIQUE
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Pierre Aumond. Modélisation numérique pour l'acoustique environnementale : simulation de champs météorologiques et intégration dans un modèle de propagation. Acoustique [physics.class-ph]. UNIVERSITE DU MAINE, 2011. Français. ⟨tel-00850700⟩

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