Sound in form of speech or music paves the way for human interaction. Noise, however, can cause severe health issues and negatively impacts our well-being and environment. Increasing urbanisation and traffic loads make reaching current noise protection goals even more challenging and require innovative and effective noise insulation technologies like acoustic metamaterials. These comprise arrays of locally resonant microstructures tuned to cancel undesired vibro-acoustic patterns such as engine noise. However, current design methods are either computationally expensive or unwarrantedly assume perfect periodicity and a lack of boundary-layer effects. These assumptions often result in incorrect or sub-optimal designs regarding the functionality and manufacturing process of the metamaterials.
The research project targets the development of a novel numerical method for the investigation and design of acoustic metamaterials. The hypothesis is that it is possible to conceive and validate a multi-physics simulation model that accurately accounts for fluid-structure interaction and boundary-layer effects, like viscothermal losses, while being efficient enough to handle large aperiodic models. A novel approach based on the boundary element method (BEM) for flow-free acoustics is pursued. The viscothermal discontinuous BEM accounts for the boundary-layer effects and their absorption potential. The method is further extended by bi-directional coupling conditions for fluid-structure interaction. Finally, the Fast Multipole Method efficiently solves the system of equations on modern heterogeneous hardware architectures.