Acoustic Scattering by Reflective Barrier Geometries

Attenuation of sound by barriers is of much practical interest for abatement of highway and urban rapid transit noise. An effective attenuation prediction scheme cannot be based on the usual diffraction from a rigid semi‐infinite plane concept because the ground effect creates localized regions of high attenuation. Assuming a coherent line source radiating above a reflecting plane, theoretical expressions are derived for the scattered sound field of semi‐elliptic and wedge‐shaped acoustically opaque barriers. Theoretical insertion loss predictions, at several measurement locations in the diffracted field, show major dependenceies on the source's position and frequency, but only a minor dependency on barrier shape. Experimental measurements agree favorably with theoretical predictions.