Speaker
Description
Sound fields in rooms containing extended reaction materials can be predicted using numerical wave methods, such as finite difference or finite element methods. To describe the material's acoustic behaviour, an equivalent fluid model is often employed. This model typically includes complex-valued, frequency-dependent descriptions of the material's effective density and effective sound speed. The effective sound speed is typically lower than that of the surrounding air, and because mesh resolution depends on the wavelength of the propagating sound wave, the mesh in the fluid region needs to be much finer than in the air-filled region. This requirement for a refined mesh in the fluid region results in models that can be costly to solve. More efficient models may be achieved through hybridization of methods, in which the air-filled region is modelled using the finite element method while the equivalent fluid region is modelled using an alternative, more efficient method. In this study, a range of hybrid models is compared in terms of their efficiency and accuracy. A simple 2D test case is used to evaluate under which conditions a hybrid model outperforms a purely finite element model for achieving the same level of accuracy.