Noise reduction by a barrier having a random edge profile
作者:
Steve S. T. Ho,
Ilene J. Busch-Vishniac,
David T. Blackstock,
期刊:
The Journal of the Acoustical Society of America
(AIP Available online 1997)
卷期:
Volume 101,
issue 5
页码: 2669-2676
ISSN:0001-4966
年代: 1997
DOI:10.1121/1.418508
出版商: Acoustical Society of America
数据来源: AIP
摘要:
Sound generally reaches the shadow zone behind a noise barrier by diffraction, or scattering, from the edge at the top of the barrier. By redirecting the incident sound into the shadow zone, the edge acts as a line source. For the traditional straight-edge barrier, the line source is coherent. Since a crooked line source is less coherent, we propose to improve barrier performance by making the edge randomly jagged. Laboratory model experiments to compare insertion loss of straight- and jagged-edge barriers are reported here. A spark was used as a point source, the barriers were thin (compared to a wavelength), and ground and meteorological effects were not important. After preliminary measurements showed that a jagged edge can produce significantly more insertion loss at high frequency, a three level full factorial experiment was done. The results led to an empirical equation for insertion loss of a jagged-edge barrier. Improvement over the straight barrier was found to increase with jaggedness. An unexplained result was the poorer performance of the jagged-edge barrier at low frequency.
点击下载:
PDF
(220KB)
返 回