Outdoor propagation models with and in the absence of barriers

Abstract

Analytic models for predicting the propagation of noise outdoors over uniform, flat terrain covered by a variety of ground covers have been proposed by the author and other researchers. These mathematical models are compared analytically and numerically for few ground cover impedances. Furthermore, when the terrain is partly covered by a hard pavement and partly by an absorbent ground, the models must take account of this discontinuity in the ground impedance. A review of the few analytic models developed by the author and other researchers is given and compared analytically and numerically. If a noise barrier is erected on a uniformly covered ground or over a pavement‐absorbent ground, then the barrier performance is affected by the ground absorption. Various empirical analytic models based on geometrical acoustics and diffraction, which account for multiple diffraction by barriers located on an absorbent ground, are reviewed. [Work supported by FHWA.]