School of Mechanical Engineering, The University of Adelaide, South Australia 5005, Australia.
J Acoust Soc Am. 2011 Apr;129(4):EL154-60. doi: 10.1121/1.3565472.
This letter presents an experimental study on the tonal noise generated by a sharp-edged flat plate at low-to-moderate Reynolds number. Flow and far-field noise data reveal that, in this particular case, the tonal noise appears to be governed by vortex shedding processes. Also related to the existence of the tonal noise is a region of separated flow slightly upstream of the trailing edge. Hydrodynamic fluctuations at selected vortex shedding frequencies are strongly amplified by the inflectional mean velocity profile in the separated shear layer. The amplified hydrodynamic fluctuations are diffracted by the trailing edge, producing strong tonal noise.
这封信介绍了一项关于低至中等雷诺数下锐缘平板产生的音调噪声的实验研究。流场和远场噪声数据表明，在这种特殊情况下，音调噪声似乎是由涡脱落过程控制的。与音调噪声的存在相关的还有一个位于后缘上游的轻微分离流区域。在分离剪切层中，弯曲的平均速度分布强烈地放大了选定涡脱落频率下的流体动力波动。放大后的流体动力波动被后缘衍射，产生强烈的音调噪声。
