MATHEMATICAL MODELING OF ENVIRONMENTAL NOISE GENERATED BY ROTORCRAFT OVERFLIGHT
OF Orikpete, TG Leton, Dre Ewim
Abstract
In applied physics, mathematical modeling is the process of describing physical phenomenon such as environmental noise by use of formulae. In testing mathematical models against actual data, the predicted data is compared with the actual data to determine if it fits the developed equation. The Noise gap index (NGI) is a metric that can be used to link rotorcraft over-flight noise with annoyance. The aim of this paper is to develop a mathematical model for Noise Gap Index (NGI) as a function of rotorcraft over-flight and background noise. Objective field measurements were carried out at twenty different locations with equal spread around Mgbuoshimini Community (Nigeria) from 0700-1700 hours for 7 days per location. Spatial distribution of NGI within the study area showed lowest NGI values occur south of the study area and highest NGI values occur north of the study area. A polynomial model was developed for background noise and plot of predicted background noise and actual data yielded a coefficient of determination “R2” value of 0.64 which was statistically significantly (P < 0.05) at 5 % level of significance. An exponential model was developed for rotorcraft noise and plot of predicted aircraft noise and actual aircraft yielded a coefficient of determination “R2” value of 0.73 which was statistically significantly (P < 0.05) at 5 % level of significance. It was concluded that receptors in areas with high background noise are prone to more annoyance from rotorcraft over-flight, than those in areas with low background noise.