Reduced Modal Modelling of Time-Domain Propagation in Complex Waveguide Networks
Résumé
The aim of this paper is to present a new model for the time domain sound propagation in complex waveguide networks. The method is based on a previous characterization in the frequency domain of each of the elements forming the network (waveguides and junctions). This characterization is performed using a mode matching technique and the information obtained is traduced to the time domain using Fourier analysis. In the time domain, spatial discretization is not required and the problem to solve is one-dimensional: the only unknown is the modal amplitude within the waveguides. Therefore, the model proves quite efficient numerically and is well suited for applications involving extended propagation domains, as in urban acoustics, that is the main motivation of the work. Furthermore, the model takes into account the complexity of the medium, as the attenuation and dispersion. Without loss of generality, the present study is limited to the propagation of the first propagating mode. Several examples are presented and compared to experiments in order to check the validity of the model, showing a good agreement between both results.