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Urban Background Noise Mapping: The Multiple-Reflection Correction Term

2014; S. Hirzel Verlag; Volume: 100; Issue: 2 Linguagem: Inglês

10.3813/aaa.918709

1610-1928

Maarten Hornikx, Jens Forssén, Dick Botteldooren, Timothy Van Renterghem, Weigang Wei, Mikael Ögren, Erik M. Salomons,

Vehicle Noise and Vibration Control

Mapping of road traffic noise in urban areas according to standardized engineering calculation methods systematically results in an underestimation of noise levels at areas shielded from direct exposure to noise, such as inner yards.In most engineering methods, road traffic lanes are represented by point sources and noise levels are computed utilizing pointto-point propagation paths.For a better prediction of noise levels in shielded urban areas, an extension of engineering methods by an attenuation term A can has been proposed, including multiple reflections of the urban environment both in the source and in the receiver area.The present work has two main contributions for the ease of computing A can .Firstly, it is shown by numerical calculations that A can may be divided into independent source and receiver environment terms, A s and A r .Based on an equivalent free field analogy, the distance dependence of these terms may moreover be expressed analytically.Secondly, an analytical expression is proposed to compute A s and A r for 3D configurations from using 2D configurations only.The expression includes dependence of the street width-to-height ratio, the difference in building heights and the percentage of façade openings in the horizontal plane.For the expression to be valid, the source should be separated from the receiver environment by at least four times the street width.