Acoustical performance of noise barrier with acoustic wells on its top edge

In this paper, the acoustic performance of noise barriers with acoustical wells on its top edge is investigated. The sound diffraction angle and insertion loss behind the barrier with acoustic wells is compared with the results of a normal straight edge barrier. Scale model experiments are carried out in fully anechoic chamber and a 2D finite element numerical model (FEM) are also used to compute the insertion loss of those barriers for validation. The results obtained by these methods show similar patterns. Using a barrier with acoustic wells is found to improve the acoustic performance of barriers compare with the normal straight edge barrier within the examined zone behind the barrier in frequency range of interest. Also, it is found that the effective operation frequency can be expanded by adding additional wells at appropriate locations. However, results show that the efficiency of the barrier will be dominated by the acoustic well near to the front edge where the first sound diffraction occurs. These findings are particularly useful to enhance the barrier performance in specific frequency range.