An experimental study of propeller noise due to cyclic flow distortion
An experimental study of propeller noise due to cyclic flow distortion
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循环流畸变引起的螺旋桨噪声实验研究
DOI：
10.1006/jsvi.1995.0295
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发表时间：
1995
影响因子：
4.7
通讯作者：
T. Mueller
中科院分区：
文献类型：
--
作者：
S. Subramanian;T. Mueller
螺旋桨进近流中的大尺度非均匀性导致周期性的非定常叶片力，其在叶片通过频率及其高次谐波处辐射音调噪声。本文通过实验研究了匹配和非匹配循环畸变对四叶螺旋桨自由场方向性的影响。该研究采用了非均匀流发生器，提供了三个周期和四个周期的流场的方位角畸变。由于流入失真只包含一个主要的傅立叶模式，一个定义良好的轴对称自由场方向性只存在于基音。源自小尺度流动梯度的高次谐波具有随机方向性。一个广泛的比较测量音调噪声水平与理论预测显示出良好的协议，无论是在幅度和方向性。
Large scale non-uniformities in the approach flow to a propeller result in periodic unsteady blade forces that radiate tonal noise at the blade passing frequency and its higher harmonics. The current research experimentally investigates the free-field directivity of a four-bladed propeller interacting with matched and mismatched cyclic distortions. The study employs non-uniform flow generators that provide a three-cycle and four-cycle azimuthal distortion of the flow field. As the inflow distortions contain just one dominant Fourier mode, a well-defined axisymmetric free-field directivity exists only for the fundamental tone. Higher harmonics, originating from small scale flow gradients, have a random directivity. An extensive comparison of the measured tonal noise levels with the theoretical predictions shows an excellent agreement, both in magnitude and directivity.