Conference paper

Influence of reflecting walls on edge diffraction simulation in geometrical acoustics

Edge diffraction can be introduced into Geometrical Acoustics mainly by three models: detour-based, energetic and wave-based diffraction models. In the past, we thoroughly compared Maekawa's detour law, the uncertainty relation based diffraction method and the secondary source model by the example of edge diffraction of a single wedge. However, the influence of the wedge shape has not yet been analyzed. Therefore, we consequently study in this contribution the influence of the wedge's faces. This is analyzed by varying both the faces' reflection properties and their opening angle. This is extended to the crucial case of approximately parallel faces (inner angle e.g.179°), where diffraction is physically neglectable, but computationally problematic for the uncertainty based diffraction method. Additionally, wedges are placed on an infinitely long surface. Therewith, we can analyze the floor reflections' impact on the sound field behind the wedge by varying both their absorption and scattering coefficients. Furthermore, we discuss artifacts which can arise in the uncertainty based diffraction model due to arbitrary positioning of diffraction planes, so called 'transparent walls'. Finally, we discuss the advantages and disadvantages of the presented methods.

Related material