Acoustic Evaluation of Single Gutters with Different Design Configurations alongside Highways

Environmental noise pollution is among the most urban problems which can be caused due to real sources like traffic, train and virtual sources provided by rigid surfaces. One of the urban structures in which can perform as a virtual noise source are the installed gutters alongside highways. These structures are mostly used to pass the wastewater or the rainfall. In this research, the acoustical performance of a gutter when the receivers are located on the top surface of gutter or in its shadow zone is investigated. To compute the acoustical efficiency of gutters, a 2D Boundary Element Method (BEM) is used. Investigation on the top surface of a simple gutter has shown that the total sound pressure has been changed and results in some disturbance. Various shapes have been studied to decline such disturbance. It was found that sound pressure of the model with curved basement was scattered steadier and the sound pressure for gutter models with wide basement was lower than the ones with narrow basement. Efficiency of some designed models was also compared in the shadow zone. Increase in depth and wide of gutter models either on the top or bottom surface has enhanced the performance of simple reference model. Considering the insertion loss computations, the amount of overall improvement in models with higher depths was more than widen models because of shifting effective performance toward lower frequencies.