“虚墙”法及其在交通噪声计算中的应用

本文提出“虚墙”法作为众所周知的虚声源法的对偶,并将它应用于车行隧道和城市街道等混响声场的交通噪声计算。根据这个概念,由单车种等间距分布的车流所产生的声场可等效于位于—对假想的刚硬墙壁之间的单一车辆所产生的声场。这对虚墙与隧道或街道的边界形成一个围闭空间,使得经典室内声压级计算公式可以应用于计算交通噪声混响声压级。本文还给出两个应用实例与实测数据相比较。

Image walls a new concept for simple estimates of traffic noise

The concept of image walls as a counterpart of the well known image source concept is introduced and applied to the calculation of traffic noise levels under reverberant conditions like in a long linear street tunnel or in urban streets. According to this concept a traffic stream of equally spaced vehicles with identical acoustic power output is equivalent to just one source situated between a pair of rigid image walls. This pair of walls, together with the tunnel's boundaries form an enclosure for which the classical formulae frorm room acoustics may be used for calculating the reverberant traffic noise sound pressure levels. Two application examples are given and compared with measured data.