A study on the acoustic performance of tramway low-height noise barriers : gradient-based numerical optimization and experimental approaches

Abstract : Noise has become a main nuisance in urban areas to the point that according to the World Health Organization 40% of the European population is exposed to excessive noise levels, mainly due to ground transportation. There is therefore a need to find new ways to mitigate noise in urban areas. In this work, a possible device to achieve this goal is studied: a low-height noise barrier. It consists of a barrier typically less than one meter high placed close to a source, designed to decrease the noise level for nearby pedestrians and cyclists. This type of device is studied both numerically and experimentally. Tramway noise barriers are especially studied since the noise sources are in this case very close to the ground and can therefore be attenuated efficiently. The shape and the surface treatment of the barrier are optimized using a gradient-based method coupled to a 2D boundary element method (BEM). The optimization variables are the node coordinates of a control mesh and the parameters describing the surface impedance. Sensitivities are calculated efficiently using the adjoint state approach. Numerical results show that the shapes generated by the optimization algorithm tend to be quite irregular but provide a significant improvement of more than 5 dB (A) compared to simpler shapes. Utilizing an absorbing treatment on the source side of the barrier is shown to be efficient as well. This second point has been confirmed by scale model measurements. In addition, a full scale low height noise barrier prototype has been built and tested in situ close to a tramway track in Grenoble. Measurements show that the device provides more than 10 dB (A) of attenuation for a close receiver located at the typical height of human ears. These results therefore seem to confirm the applicability of such protections to efficiently decrease noise exposure in urban areas
Document type :
Theses
Complete list of metadatas

Cited literature [178 references]  Display  Hide  Download

https://pastel.archives-ouvertes.fr/pastel-00965168
Contributor : Abes Star <>
Submitted on : Monday, March 24, 2014 - 5:19:21 PM
Last modification on : Thursday, January 11, 2018 - 6:25:23 AM
Long-term archiving on : Tuesday, June 24, 2014 - 12:50:46 PM

File

TH2013PEST1116_complete.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : pastel-00965168, version 1

Citation

Alexandre Jolibois. A study on the acoustic performance of tramway low-height noise barriers : gradient-based numerical optimization and experimental approaches. Other. Université Paris-Est, 2013. English. ⟨NNT : 2013PEST1116⟩. ⟨pastel-00965168⟩

Share

Metrics

Record views

545

Files downloads

1153