Modeling of cylindrical baffle mufflers for low frequency sound propagation
Résumé
Baffle mufflers are widely used in building airflow systems. These mufflers are made up of diaphragms and porous materials inserted in constant section ducts. This work is focus on the low frequency range [63-500] Hz and considers a cylindrical geometry. The aim of this study is to predict the acoustic transmission loss of such silencer in order to improve its efficiency. The first step presented in this paper deals with the muffler insertion into an air-free flow networks using the transfer matrix method. Indeed an analytical low frequency approach computes the global transfer matrix of one cylindrical muffler, analogous to two diaphragms in series with porous material in-between. The first transverse mode is taking into account in the two discontinuities as well as a pseudo plane wave in the porous-air section [Journal of Sound and Vibration (2001) 243(3), 461-473]. Results are then compared with experiments and simulation by finite element method. The effect of the porous material thickness, the baffle length and geometry are finally highlighted.
Domaines
Acoustique [physics.class-ph]Origine | Fichiers éditeurs autorisés sur une archive ouverte |
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