An efficient MFS model for the analysis of sonic crystals including fluid-solid interaction

Sonic crystals are a relatively recent concept that is being explored for different applications. Several types of models exist in literature for their analysis, although in many cases they consider their elements to be rigid. In this work, the authors propose a hybrid numerical-analytical model based on the Method of Fundamental Solutions (MFS) to address the problem of sound scattering by a sonic crystal composed of non-rigid scatterers. This model would account for the full interaction between the acoustic medium and an array of elastic shell structures, which are assumed to be circular and filled with fluid. For that purpose, each scatterer is accounted for by means of a closed form solution, and the full set of scatterers is then coupled by means of the MFS. This strategy allows a compact description of the propagation medium while being very accurate and efficient from the computational point of view. Application examples are presented considering structures embedded in different acoustic media (air or water), and using the sonic crystal either as a waveguide or as a sound barrier.