On high-frequency noise scattering by aerofoils in flow
On high-frequency noise scattering by aerofoils in flow
复制标题
流动中机翼的高频噪声散射
DOI：
10.1017/jfm.2013.477
复制
发表时间：
2013
影响因子：
3.7
通讯作者：
Ayton L
中科院分区：
文献类型：
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作者：
Ayton L
建立了声波以非零迎角入射到弧形翼型上时的声散射理论模型。该模型基于定常亚声速流欧拉方程的线性化，是对前人考虑入射涡扰动的修正。只考虑高频声波。翼型厚度、外倾角和攻角受到限制，使得流过机翼的定常流动是对均匀流动的微小扰动。奇异摄动分析确定了机翼周围的渐近区域；在机翼前缘和后缘随入射波长变化的局部“内”区域；由于奇点和静止相点的结合而从机翼前缘和后缘发出的菲涅耳区域；机翼前缘和后缘下游的尾迹转换区；以及远离机翼和尾迹的外部区域。翼型表面和过渡区内的声学边界层解释了曲率的影响。最后得到了远场声场的一致有效解，并研究了攻角、外倾角和厚度对远场声场的影响。
A theoretical model is developed for the sound scattered when a sound wave is incident on a cambered aerofoil at non-zero angle of attack. The model is based on the linearization of the Euler equations about a steady subsonic flow, and is an adaptation of previous work which considered incident vortical disturbances. Only high-frequency sound waves are considered. The aerofoil thickness, camber and angle of attack are restricted such that the steady flow past the aerofoil is a small perturbation to a uniform flow. The singular perturbation analysis identifies asymptotic regions around the aerofoil; local ‘inner’ regions, which scale on the incident wavelength, at the leading and trailing edges of the aerofoil; Fresnel regions emanating from the leading and trailing edges of the aerofoil due to the coalescence of singularities and points of stationary phase; a wake transition region downstream of the aerofoil leading and trailing edge; and an outer region far from the aerofoil and wake. An acoustic boundary layer on the aerofoil surface and within the transition region accounts for the effects of curvature. The final result is a uniformly-valid solution for the far-field sound; the effects of angle of attack, camber and thickness are investigated.
DOI：
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发表时间：
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期刊：
影响因子：
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作者：
Philip Heywood;D. S. Jones
通讯作者：
D. S. Jones