Quadrupole noise generated from a low-speed aerofoil in near- and full-stall conditions
Quadrupole noise generated from a low-speed aerofoil in near- and full-stall conditions
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近失速和全失速条件下低速机翼产生的四极噪声
DOI：
10.1017/jfm.2022.75
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发表时间：
2022
影响因子：
3.7
通讯作者：
Turner J
中科院分区：
文献类型：
--
作者：
Turner J
在本文中，对以高入射角流过 NACA0012 翼型的低速流动进行了直接数值模拟。目的是研究与翼型表面发出的偶极噪声相比，由于分离的剪切层而产生的四极噪声的重要性。两种不同的噪声分量（偶极子和四极子）是通过使用 Ffowcs Williams & Hawkings 方法以两种不同的方法计算的：一种使用固体表面，另一种使用可渗透表面。然后通过获取两者之间的相对差来近似估计四极噪声。当前的研究提供了各种频率范围内不同观察者位置的四极和偶极噪声分量之间的详细比较。还根据马赫数标度进行了比较，马赫数标度与理论预测有很大不同，并且随频率快速变化。此外，对预失速、近失速和全失速条件进行了交叉检查，揭示了四极杆贡献的显着差异，包括主要源位置和频率的变化。研究发现，与仅使用偶极子的情况相比，包含四极子源会导致所有频率下的预测噪声功率水平（对于机翼上方的观察者而言，噪声功率在 2 到 10 dB 之间变化）。即使在低亚音速（0.3 和 0.4 马赫）发生机翼失速时，四极杆的贡献也不容忽视。
In this paper, direct numerical simulations are performed for low-speed flows past a NACA0012 aerofoil at high incidence angles. The aim is to investigate the significance of quadrupole noise generated due to separated shear layers, in comparison to dipole noise emanating from the aerofoil surface. The two different noise components (dipole and quadrupole) are calculated by using the Ffowcs Williams & Hawkings method in two different approaches: one with a solid surface and another with a permeable surface. The quadrupole noise is then estimated approximately by taking the relative difference between the two. The current study provides detailed comparisons between the quadrupole and dipole noise components at various observer locations in a wide range of frequencies. The comparisons are also made in terms of Mach number scaling, which differs significantly from theoretical predictions and changes rapidly with frequency. Additionally, pre-, near- and full-stall conditions are cross-examined, which reveals significant differences in the quadrupole contributions, including changes in the major source locations and frequencies. It is found that the inclusion of the quadrupole sources gives rise to the predicted noise power level at all frequencies (varying between 2 and 10 dB for an observer above the aerofoil) compared to the dipole-only case. The quadrupole contribution is far from negligible even at the low subsonic speeds (Mach 0.3 and 0.4) when aerofoil stall occurs.
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影响因子：
2
作者：
G. Lacagnina;P. Chaitanya;T. Berk;Jung‐Hoon Kim;P. Joseph;B. Ganapathisubramani;S. Hasheminejad
通讯作者：
G. Lacagnina;P. Chaitanya;T. Berk;Jung‐Hoon Kim;P. Joseph;B. Ganapathisubramani;S. Hasheminejad
使用高阶方案计算经过锥体的亚音速无粘流
DOI：
--
发表时间：
2002
期刊：
影响因子：
--
作者：
J. Kim;P. Morris
通讯作者：
P. Morris
DOI：
10.1016/j.ijheatfluidflow.2020.108715
发表时间：
2020-12
影响因子：
2.6
作者：
J. Turner;J. Kim
通讯作者：
J. Turner;J. Kim
影响因子：
4.7
作者：
DiFrancescantonio, P
通讯作者：
DiFrancescantonio, P
近失速或失速翼型的流动特性及自噪声
DOI：
--
发表时间：
2009
期刊：
影响因子：
--
作者：
S. Moreau;M. Roger;J. Christophe
通讯作者：
J. Christophe