缓速脊对轻型车噪声的影响分析

车辆通过缓速脊时,因行驶状态发生变化而引起车辆噪声的变化。车辆在接近缓速脊的减速阶段噪声降低,在通过缓速脊后的加速阶段噪声增加,缓速脊对轻型车噪声的影响可用声源辐射能量的线性密度S加以评估。车辆和缓速脊间瞬时距离为x,要确定函数S(x),对于每辆车需要5个声曝级的测量值。本文假定每辆车为无方向点声源,产生的噪声在传播过程中无垂直于表面的反射,并基于此给出轻型车声曝级的测算方法。

Predicted effects of a speed bump on light vehicle noise

A speed bump reduces traffic noise levels during the deceleration phase and increases them during the cars go through a speed bump.The net effect of a speed bump on noise from a light vehicle is assessed by means of the concept of noise energy density,S.This is a function of the instantaneous distance between the vehicle and the bump,S(x). To determine the function S(x) explicitly, five mea- surements of the sound exposure level, for each vehicle,are needed.It is assumed that the noise from each vehicle is generated by a single non-direc- tional point source and propagates without verti- cal-surface reflections.An example prediction is presented based on measurements of sound exposure levels due to passenger cars.