Optimization of the poro-serrated trailing edges for airfoil broadband noise reduction.
Optimization of the poro-serrated trailing edges for airfoil broadband noise reduction.
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DOI：
10.1121/1.4961362
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发表时间：
2016-08
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影响因子：
--
通讯作者：
T. Chong;E. Dubois
中科院分区：
文献类型：
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作者：
T. Chong;E. Dubois
本文报道了对 NACA0012 翼型的气动声学研究，该翼型具有多个多孔锯齿状后缘装置，这些装置在锯齿状锯齿状后缘的相邻构件之间的间隙处包含具有不同气流阻力的多孔材料。这项工作的主要目的是确定宽带降噪的多种机制是否可以在多孔锯齿状后缘上共存。当锯齿间隙填充低流阻率的多孔材料时，低频时的涡旋脱落音在高速时无法完全抑制，但在高频时可以实现相当好的宽带降噪。当锯齿间隙填充流动电阻率非常高的多孔材料时，不存在涡旋脱落音，但锯齿对宽带噪声降低的效果变得不太有效。已经确定了多孔锯齿结构的流阻率的最佳选择，它可以通过实现宽带噪声进一步降低 1.5 dB，同时完全抑制涡旋脱落音来超越相同几何形状的传统锯齿后缘。锯齿状后缘处的湍流边界层噪声散射减弱，反映在锯齿的整个展向波长上近尾流中心线处的较低湍流强度。
This paper reports an aeroacoustic investigation of a NACA0012 airfoil with a number of poro-serrated trailing edge devices that contain porous materials of various air flow resistances at the gaps between adjacent members of the serrated-sawtooth trailing edge. The main objective of this work is to determine whether multiple-mechanisms on the broadband noise reduction can co-exist on a poro-serrated trailing edge. When the sawtooth gaps are filled with porous material of low-flow resistivity, the vortex shedding tone at low-frequency could not be completely suppressed at high-velocity, but a reasonably good broadband noise reduction can be achieved at high-frequency. When the sawtooth gaps are filled with porous material of very high-flow resistivity, no vortex shedding tone is present, but the serration effect on the broadband noise reduction becomes less effective. An optimal choice of the flow resistivity for a poro-serrated configuration has been identified, where it can surpass the conventional serrated trailing edge of the same geometry by achieving a further 1.5 dB reduction in the broadband noise while completely suppressing the vortex shedding tone. A weakened turbulent boundary layer noise scattering at the poro-serrated trailing edge is reflected by the lower-turbulence intensity at the near wake centreline across the whole spanwise wavelength of the sawtooth.