Trailing Edge Noise Reduction Using Novel Surface Treatments
Trailing Edge Noise Reduction Using Novel Surface Treatments
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DOI：
10.2514/6.2016-2834
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发表时间：
2016-05
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影响因子：
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通讯作者：
A. Afshari;A. Dehghan;M. Azarpeyvand;Máté Szőke
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文献类型：
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作者：
A. Afshari;A. Dehghan;M. Azarpeyvand;Máté Szőke
本文提出并试验了一种新的后缘噪声控制技术，该技术基于上游操纵大的相干湍流结构，采用二维表面处理。为了证明拟议的后缘噪声控制技术的能力，一个长的平板模型，配备了几个流向和展向表面压力麦克风，已被设计和建造。已经对具有不同几何图案和尺寸的各种表面处理进行了流动和噪声测量。采用单探针热线风速仪研究了表面处理下游的流动行为。结果表明，使用这种表面处理可以导致后缘附近的表面压力波动降低约8 dB。更重要的是，已经观察到，展向相干性可以在很宽的频率范围内显着减少，这意味着大的相干湍流结构已成功地从边界层中去除。此外，非定常表面压力和边界层速度互相关的研究表明，边界层外部区域内的湍流结构和施加在表面上的非定常表面压力之间的相关性可以通过使用高度仅为边界层厚度的10%的处理来显著降低
A novel trailing edge noise control technique based on upstream manipulation of large coherent turbulent structures using two dimensional surface treatments has been proposed and tested. To demonstrate the capabilities of the proposed trailing edge noise control technique, a long flat-plate model, equipped with several streamwise and spanwise surface pressure microphones, has been designed and built. Flow and noise measurements have been carried out for a variety of surface treatments, with different geometrical patterns and dimensions. The flow behavior downstream of the surface treatment is also studied by employing a single probe hotwire anemometer. Results have shown that the use of such surface treatments can lead to around 8 dB reduction of the surface pressure fluctuations near the trailing edge. More importantly, it has been observed that the spanwise coherence can be significantly reduced over a wide range of frequencies, implying that the large coherent turbulent structures have been successfully removed from the boundary layer. Furthermore, the unsteady surface pressure and boundary layer velocity cross-correlation studies have shown that the correlation between the turbulent structures within the outer region of the boundary layer and the unsteady surface pressure exerted on the surface can be significantly reduced by using treatments with height of only 10% of the boundary layer thickness