Investigation of the aerodynamic noise generating region of a jet engine by means of the simple source fluid dilatation model
Investigation of the aerodynamic noise generating region of a jet engine by means of the simple source fluid dilatation model
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利用简单源流体膨胀模型研究喷气发动机气动噪声产生区域
DOI：
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发表时间：
1974
期刊：
影响因子：
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通讯作者：
B. Hodder
中科院分区：
文献类型：
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作者：
P. Hurdle;W. Meecham;B. Hodder
在全尺寸喷气发动机上进行了实验，以研究自由射流中的气动噪声产生区域。在静压波动和远场辐射声之间进行互相关测量。这些测量是在两个不同的静压探头位置和大量远场位置（不同角度）进行的。此外，每个测试几何形状运行四个不同的射流出口速度。测量的归一化互相关函数在0.004和0.155之间变化。定义并绘制了基于上述归一化互相关的新Q函数。该函数表示射流区域内每单位体积的源强度。该Q函数显示了对探头位置、远场麦克风的角位置和射流出口马赫数的依赖性。对探头信号和远场辐射声进行了第三倍频程分析。结果表明，互相关技术是一个有价值的工具，在调查的气动噪声产生区域的实际喷气发动机。
An experiment was conducted on a full‐scale jet engine to investigate the aerodynamic noise generating regions in the free jet. Cross‐correlation measurements were made between the static pressure fluctuations and the farfield radiated sound. These measurements were made for two different static pressure probe positions and a large number of farfield positions (at various angles). In addition, each test geometry was run for four different jet exit velocities. The measured, normalized cross‐correlation functions varied between 0.004 and 0.155. A new Q‐function, based on the above normalized cross correlation is defined and plotted. This function represents the source strength per unit volume within the jet region. This Q‐function shows dependence on the probe position, the angular position of the farfield microphone, and the jet exit Mach number. Third‐octave analyses of both the probe signal and the farfield radiated sound were made. The results show that cross‐correlation techniques are a valuable tool in the investigation of the aerodynamic noise generating regions of an actual jet engine.