Numerical predictions for environmental acoustics : simulation of atmospheric fields and integration in a propagation model
Résumé
Outdoor sound prediction is both a societal stake and a scientific issue. Thus this paper deals with numerical simulations of micrometeorological (temperature and wind) fields for environmental acoustics. This is carried out through new developments in the reference mesoscale meteorological model at Météo-France (Meso-NH). Meso-NH predictions at very fine scales (up to 1m) including new developments (drag force approach) are validated both numerically and experimentally under stable, unstable and neutral conditions. Then, this information can be used as input data for acoustic models. Our time domain acoustic model is based on the Transmission Line Matrix method (TLM). Its development has been carried out in order to be applied to outdoor sound propagation, i.e. in order to take into account topography, ground impedance, meteorological conditions, etc. The numerical validation of the TLM method by comparison with other models shows the relevance of its use in the context of environmental acoustics. Finally, thanks to these models, simulated noise levels in different propagation conditions were compared to in situ measurements. Satisfying results were obtained regarding the observed phenomena variability. A feasibility study on a more complex experience (LTMS) leads to consider the TLM as a promising method in the context of environmental acoustics.