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27 mars 2019: 1 événement

  • Séminaires Invités

    Mercredi 27 mars 14:00-15:30 - Rodolfo Venegas - University of Salford, Salford, United Kingdom

    Acoustic wave propagation in multiscale sorptive porous materials

    Résumé : The microstructure of multiscale sorptive porous materials features pores or inclusions of very different characteristic sizes ranging from nanometers to millimeters. We investigate acoustic wave propagation in multiscale rigid-frame porous materials that support sorption and different types of diffusion in addition to the usual visco-thermo-inertial interactions. We make successive use of the two-scale asymptotic method of homogenization to derive effective equations that describe sound propagation through the material macroscopically. This allows us to conclude that the macroscopic mass balance is significantly modified by sorption, inter-scale mass diffusion, and inter-scale pressure diffusion.
    This modification is accounted for by the dynamic compressibility of the effective saturating fluid that presents atypical properties that lead to slower speed of sound and higher sound attenuation, particularly at low frequencies. We validate the theory by comparing the predictions of an analytical model with experimental data for activated carbons and provide evidence supporting a measurement method for sorption and mass diffusion properties using sound waves.
    Bonus : Applications of sorptive materials in audio, acoustics and dynamics
    We discuss applications of multiscale sorptive porous materials to improve the acoustic performance of loudspeakers, enhance sound absorption by resonators, reduce sound transmission through wall partitions and reduce the form factor of gas springs.

    contact : Benoit Coasne

    Lieu : LIPhy, conference room - 140 Avenue de la Physique 38402 Saint Martin d’Hères

    En savoir plus : Séminaires Invités