Some considerations on the simulation of meta-materials acoustic behavior

One of the major advantages behind the success of metamaterials is related to the possibility to design them based on theoretical assumptions or when theory gets complicated, thanks to numerical methods. Many efforts have been made in the last years to better support researchers with benchmark tools that allow us to make their calculations more reliable, offering the opportunity to directly model the sound propagating inside the material or allow the determination of the parameters that can be used to feed phenomenological models. However, like any other simulation tool, a proper knowledge of the physics and the ways it is approximated are required to get the best results. The paper presents a selection of issues that may play a relevant role to improve the final results, including geometrical discretization, modelling of boundary conditions, and use of periodical structures. A discussion follows also pointing out the differences pertaining to transmission and absorption problems.