Investigating the stability of frequency-dependent locally reacting surface boundary conditions in numerical acoustic models.

Numerical acoustic modeling enables simulation of sound propagation through bounded space. Recent research directed to refining Finite Difference Time Domain solutions for acoustic prediction has focused on emulating sound wave-surface interaction. Locally reacting surface properties are a popular choice for deriving boundary conditions that incorporate surface absorption properties. However, implementation of these boundary conditions, using the methods described in prevalent literature, is demonstrated here as unstable for complex room geometries. This work presents a reformulated implementation of frequency-dependent locally reacting surface boundary conditions for Finite Difference Time Domain simulations that is empirically demonstrated to be robust against simulation instabilities.