Acoustics Research Centre, Department of Electronics and Telecommunications, Norwegian University of Science and Technology, 7491 Trondheim, Norway.
J Acoust Soc Am. 2011 Oct;130(4):1851-5. doi: 10.1121/1.3628665.
It is well known that airflow in a corrugated pipe can excite whistling at the frequencies of the pipe's longitudinal acoustic modes. This short contribution reports on the results of experiments where a low frequency, oscillating flow with velocity magnitudes of the same order as the airflow has been added. Depending on the oscillation strength, it has been found that this flow may silence the pipe or move the whistling to higher harmonics. It is also shown that the low frequency oscillation itself may excite higher frequency whistling sounds in the pipe.
众所周知,波纹管中的气流会在管道的纵向声学模式频率处激发啸叫声。本短贡献报告了在实验中的结果,其中添加了低频、振荡流动,其速度大小与气流相同。根据振荡强度的不同,发现这种流动可能会使管道静音或使啸叫声移至更高的谐波。还表明,低频振荡本身可能会在管道中激发更高频率的啸叫声。