Measurements on effects of winds to road traffic noise propagations over a flat and open field

摘要

There has been a number of experimental, theoretical and numerical studies regarding wind effects on outdoor sound propagation, most of which focus on propagation from steady-state point source such as a loudspeaker in case of field measurements. However on the other hand, wind effect studies on more realistic sources, such as road traffic noise sources which are considered to be time-varying line sources, are hardly known in public literature. In the study, the wind effects to acoustic propagation from a straight road with intense traffic to a flat and open field is investigated through a series of field measurements to specifically illustrate the effects of such sources. The results show that 1) The standard deviations of SPLs at the measurement points were around 2 dB regardless of the distance from the road, 2) The effect of perpendicular component of wind velocity to the road direction was slightly stronger than the ASJ Model which was mostly derived from point-source experiments. 3) The effect of source time-variance was effectively taken out by taking the difference in SPLs at the nearby and distant measurement points, in which case the standard deviations of the excess attenuation were reduced to around 1.4 dB. Meanwhile, the effect of parallel wind velocity component to the road still remained unclear in the study and thus requires further investigations.