Modelling of excess noise attnuation by grass and forest

Abstract

A wide-range of acoustical measurements have been conducted in the open field, guinea grass ( panicum maximum ) and forest which comprises iroko ( milicia ezcelea ) and white afara ( terminalia superba ) trees in the ratio of 2:1 approximately. Excess noise attenuation spectra have been plotted for the grass and forest for various distances. It was observed that the grass introduces excess noise attenuation about twice that of the trees (or forest) throughout the octave band centre frequencies. Excess noise attenuation curves for both media indicate three distinct parts. Results have further shown that the grass and the trees can find applications in environmental noise control and the built environment. The proposed best models for excess noise attenuation versus octave band centre frequency in this study are logarithmic (or linear) for the grass and power law for the forest. Keywords : Excess noise attenuation, grass, forest andctave band centre frequency Nigerian Journal of Physics Vol. 18 (2) 2006: pp. 197-202