Coupled FE/BE for periodic acoustic systems

While coupled finite element and boundary element (FE/BE) codes are used regularly in acoustics—particularly structural acoustics—and periodic boundary conditions are common, the combination of the three is rare. However, such calculations have been performed in the electricity and magnetism community for quite some time. This talk presents a fully coupled FE/BE framework for acoustics with doubly-periodic boundary conditions, accomplished by way of the Ewald transformation of the appropriate periodic Green’s function. This method is likely of primary interest to the acoustic metamaterials community and it is used to analyze an example problem drawn from this field. Both the internal acoustic field within the FE mesh as well as the system’s radiation characteristics are examined.