Empirical Prediction of Workshop Fitting Densities for Noise Prediction by Ray Tracing

Abstract

Empirical models were developed for predicting frequency-varying fitting densities in industrial workshops for use in the prediction of noise levels by a ray-tracing model. Eleven typical workshops with varying dimensions, types, quantities and distributions of fittings, in which octave-band sound-propagation curves and the fitting dimensions had been measured, were involved. The workshops were modeled and sound-propagation curves were predicted for a range of fitting densities. The predicted curves were compared with the measured curves to determine the ‘best-fit’ fitting density. Linear-regression analysis was then used to find empirical models for predicting the best-fit fitting densities from physical parameters calculated from the fitting and workshop dimensions. The average fitting-to-workshop height ratio, the fitting-to-workshop volume ratio and the number of fittings were the parameters that predicted the fitting density best. Preliminary validation work, involving the comparison of sound-propagation curves predicted with the empirically-predicted fitting densities by ray tracing and the curves measured in four other workshops, suggests that the empirical models are inherently valid.

Keywords

Room acoustics industrial noise industrial workshops prediction fittings fitting density ray tracing

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