Abstract

This paper deals with the acoustics of permeo-elastic media. These media comprise a rigid porous skeleton with attached elastic films that interact with the fluid that saturates the pores. The pore-scale fluid/film interaction introduces elastic energy that interacts with viscous dissipation and inertial effects. The corresponding non -conventional flow regimes are studied by the two-scale asymptotic homogenisation method by successively considering permeo-elastic media with (i) fully connected pores, (ii) strictly unconnected pores (i.e. pores closed by films), (iii) partially connected pores, and (iv) mixed morphologies. This analysis allows to precisely describe how the morphology both influences, quantitatively and qualitatively, the interaction of the elastic and kinetic energies of the films with the viscous and kinetic energies of the fluid, and modifies the effective properties. It is shown that, in specific frequency ranges, the film-fluid system behaves as an equivalent visco-elastic fluid and that local film- fluid resonances can be observed. Numerical examples illustrate the main features in the different cases. The presented synthetic approach enables the design of materials that exhibit unconventional conductivity, unconventional compressibility, or both, in different or the same frequency range, by means of tuning their morphological and/or mechanical parameters.(c) 2022 Published by Elsevier B.V.