同济气动声学风洞声场品质测试

Sound Field Performance Test of Tongji Aero-acoustic Wind Tunnel

摘要:

气动声学风洞的声场品质包括试验段驻室自由声场、背景噪声和低频压力脉动3个方面指标。同济气动声学风洞声场测试结果显示，160 km?h^-1风速的背景噪声A计权总声压级为61 dB（A），50~200 km?h^-1风速范围内的低频压力脉动系数小于0.5%；滚动路面系统的移动带抽吸在80 km?h^-1风速以下干扰背景噪声，但对低频压力脉动没有影响；按照ISO 3745∶2012标准，试验段驻室自由声场截止频率低至50 Hz，且63 Hz及以上自由声场半径达到9 m。

Abstract:

The sound field performance for an automobile aero-acoustic wind tunnel comprises three aspects of free-sound field， background noise and low-frequency pressure fluctuation. The latest test results of Tongji Aero-acoustic Wind Tunnel has validated that the background noise OASPL at 160 km?h^-1 wind speed is 61 dB（A）， and the low-frequency pressure fluctuation coefficient is lower than 0.5% within the wind speed range from 50 to 200 km?h^-1. Meanwhile， it was found that the belt suction of rolling road systems adds the background noise below 80 km?h^-1 wind speeds， yet no effects on the low-frequency pressure fluctuation. According to ISO 3745∶2012， the cut-off frequency of the free-sound field is down to 50 Hz， while the radius of the free-sound field at and above 63 Hz cut-off frequencies reaches 9 m inside test section plenum.