Date of Award

2012

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Electrical Engineering

First Advisor

Bikdash, Marwan

Abstract

Low-frequency outdoor noise is very common in urban environments and can propagate over long distances. Residents living in the vicinity of a military base and other noisy areas often are annoyed by this noise. Most of the theoretical and experimental work that have been done to study and reduce this type of noise involved the use of barriers and sound proofing the residential houses. The attenuation of acoustic waves propagating above hard surfaces over long distances depends on the shape of the surface. Therefore, the landscape is a factor in combating outdoor noise. In this dissertation, an anti-propagation approach involving the use of corrugated surfaces or sinusoidally shaped berms to suppress outdoor noise was proposed. Finite element analysis and the equivalent source method (ESM) were employed to investigate the effects of corrugated surfaces on the acoustic transmission loss. The equivalent source method (ESM) was used to model different surface geometries and employed in conjunction with a nonlinear optimization algorithm to compute the surface shape that will result in the most acoustic loss. The corrugation method was shown to be effective against certain frequencies and can be used to combat low-frequency outdoor noise.

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