考虑声散射的街道交通噪声预报模型

提出一种预报典型的两侧密集分布建筑物的城市街道交通噪声ＬＡ１０和ＬＡｅｑ声级的计算机仿真模型。模型依据一种修正的虚声源原理。它不仅考虑发生于建筑方面的镜象反射和表面吸收，而且考虑了由于墙面的粗糙性所引起的发生于有限尺寸建筑表面声散射的影响。与实测比较表明本模型可得出良好的预报结果。通过对散射强度加以变化可估计表面声散射对预报声级的影响。结果表明，即使在一个相当混响的场合，镜象反射声能对扩散反射声能

ON THE RELEVANCE OF SOUND SCATTERING FOR THE PREDICTION OF TRAFFIC NOISE IN URBAN STREETS

A computer simulation model was developed for predicting LA10 and LAeg levels of traffic noise in a typical urban configuration with buildings lining densely both sides of a street. The model is based on a modified image source principle. It considers not only specular reflection and surface adsorption, but also the effects of diffuse scattering by surface roughnesses of the scattering facades of finite size. Comparison with measured data showed that the model yielded reasonable results. By a variation of the roughness parameter it is possible to assess the impact of scattering on the predicted levels. The results obtained in this way indicate that, even in a rather reverberant situation , the predicted levels are not very sensitive to the ratio of secularly reflected to diffusely scattered energy.