Acoustic performance of a barrier embedded with Helmholtz resonators using a quasi-periodic boundary element technique

Barriers are widely used to attenuate environmental noise from vehicles to residential areas. This paper numerically explores the acoustic performance of a barrier for tailored low frequency noise reduction using a quasiperiodic boundary element method, whereby the barrier is represented by a finite number of periodic sections along its length. Results for the insertion loss of a barrier with single and multiple Helmholtz resonators embedded along the top edge of each periodic barrier section and tuned to different frequencies are compared to results for an equivalent straight barrier in the absence of the Helmholtz resonators. The acoustic performance of the noise barrier with and without the embedded Helmholtz resonators is also examined for elevated traffic noise sources typically corresponding to engine and exhaust noise of light and heavy vehicles. Diffraction over the top edge of the barrier and reflections from the ground on both the source and receiver sides of the barrier are taken into account.