NOISE GENERATED BY AIRFOIL PROFILES PLACED IN A UNIFORM LAMINAR-FLOW
NOISE GENERATED BY AIRFOIL PROFILES PLACED IN A UNIFORM LAMINAR-FLOW
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DOI：
10.1017/s0022112083003201
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发表时间：
1983-01-01
影响因子：
3.7
通讯作者：
BATAILLE, J
中科院分区：
文献类型：
--
作者：
ARBEY, H;BATAILLE, J
本文对翼型在均匀层流中产生的噪声进行了实验研究。远场声谱由频率fs附近的宽带贡献和等距频率fn处的离散贡献组成，它们遵循形式为fs <$U1.5和fn <$U0.85的幂律。这两种贡献都可以用一个简单的模型来解释，这个模型是从Tam（1974）和Fink（1975）最初的建议中推导出来的。它基本上是假设的Tollmien-Schlichting不稳定性的后缘的衍射产生的声波在远场传播，也触发了一个气动声学反馈回路，其长度等于后缘和翼型的最大速度点之间的距离。
The present paper is devoted to the experimental study of the noise generated by an airfoil profile placed in a uniform laminar flow. The far-field acoustic spectrum is shown to be composed of a broadband contribution around frequency fs and a discrete contribution at equidistant frequencies fn, which follow power laws of the forms fs ∼ U1.5 and fn ∼ U0.85. Both contributions can be accounted for by a simple model derived from the original suggestions of Tam (1974) and Fink (1975). It is essentially assumed that the diffraction of the Tollmien-Schlichting instabilities by the trailing edge generates acoustic waves which propagate in the far field and also trigger an aeroacoustic feedback loop, whose length is equal to the distance between the trailing edge and the maximum velocity point of the airfoil.