摘要
分析了桨叶间距非均匀调制对直升机旋翼厚度噪声的影响。桨叶间距按照正弦调制和余弦调制变化时,根据FW-H方程的Formulation 1A公式,计算了直升机悬停状态下的旋翼厚度噪声。桨尖速度为亚音速时的计算结果显示,与桨叶间距均匀的直升机旋翼厚度噪声相比,非均匀桨可以改变厚度噪声的频谱特征,而且在基本保持厚度噪声总声压级不变情况下,降低厚度噪声桨叶通过频率及谐频的线谱幅值。本文的分析和结果有助于认识非均匀旋翼厚度噪声的频谱变化规律。
The effect on thickness noise of helicopter rotor caused by uneven blade spacing was analyzed. For hovering rotor with uneven blade spacing modulated in sinusoidal or cosinoidal mode, its thickness noise was calculated. Thickness noise calculation method is based on Formulation 1A which is the solution of FW-H equation. Compared with thickness noise for rotor with even blade spacing, the calculation results show that the magnitude of frequency spectrum lines on blade passing frequency and its harmonics are reduced and frequency spectrum shape is changed for rotor with uneven blade spacing when tip velocity of blade is subsonic. At the same time, the overall sound pressure level of thickness noise for uneven blade spacing is approximately same with that for even blade spacing. The result could be used to analyze the frequency spectrum change of thickness noise for rotor with uneven blade spacing.
出处
《声学学报》
EI
CSCD
北大核心
2011年第5期513-519,共7页
Acta Acustica
