A BEM APPROACH TO ASSESS THE ACOUSTIC PERFORMANCE OF NOISE BARRIERS IN A REFRACTING ATMOSPHERE
✍ Scribed by K.M. Li; Q. Wang
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 402 KB
- Volume
- 211
- Category
- Article
- ISSN
- 0022-460X
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✦ Synopsis
Theoretical and experimental investigations into the acoustic performance of noise barriers in a refracting atmosphere are presented. The theory is based on the conformal transformation. It can be shown that the sound field in a refracting atmosphere with an exponential sound speed profile above a flat impedance ground is identical to the sound field in the homogeneous medium above a cylindrically curved impedance surface. The sound fields behind noise barriers can then be computed accurately by means of the Boundary Element Method (BEM). In addition, a scale model study has been conducted for experimental investigations of the sound diffraction behind thin barriers above cylindrically curved surfaces. These experimental results validate the proposed numerical scheme. Finally, the BEM is extended to predict the sound fields, in both the upward and downward refracting atmosphere, behind a thin barrier up to a range of 110 m. Also the numerical predictions based on the BEM are compared with other published experimental results.