Characterization of acoustic metasurface absorbers usingnumerical methods including viscous and thermal losses

Acoustic meta-surfaces are periodic structures commonly realised using subwavelength sized resonators. One of their possible applications is in noise control where they can be applied to create very compact sound absorbers. Numerical modelling and characterization of meta-surfaces require the inclusion of acoustic viscous and thermal dissipation effects. Several variations of numerical methods are available that include such losses, each having different computational benefits and limitations. In this work, numerical methods that incorporate dissipation are applied to study the normal absorbing properties of several meta-surface designs. The results will be used to both benchmark the different numerical methods, but also to extract data for simplified fluid equivalent models that can be used as input for large-scale simulations including meta-surfaces.