Modeling of acoustic propagation to capture finer-scale features of bounding objects.

Abstract

One of the limiting factors of performing high-resolution modeling of outdoor sound propagation in the time domain is the treatment of the boundary conditions. Impedance ground boundary conditions have been successfully modeled in the time domain for a variety of porous ground types via the use of recursive convolution methods; however, the applications were for a flat ground. The modeling of sound propagation around buildings (or other obstacles) is usually accomplished by drastically simplifying the building geometry, thereby failing to account for fine-scale, or even some larger-scale, details. Experiments conducted at a fire training facility found that external building features, such as facets and fire escapes, can effect the sound field significantly enough so that standard acoustic diffraction models fail to accurately predict the sound field. Here we develop numerical models that allow us to capture the effects of finer-scale features. Such treatments are necessary for the development of source localization algorithms in urban or other multifarious environments.