Issue |
JNWPU
Volume 38, Number 6, December 2020
|
|
---|---|---|
Page(s) | 1275 - 1283 | |
DOI | https://doi.org/10.1051/jnwpu/20203861275 | |
Published online | 02 February 2021 |
Research on Calculation Method for Acoustic Scattering of Helicopter Noise
直升机噪声声散射特性计算方法研究
Science and Technology on Rotorcraft Aeromechanics Laboratory, China Helicopter Research and Development Institute, Jingdezhen 333001, China
Received:
30
December
2019
A new calculation method of helicopter rotor/fuselage acoustic scattering is developed. Firstly, a CFD analysis model is developed to simulate flow field of the rotor, which is based on the motional embedded grid system and RANS equations, and provides aerodynamic data for rotor noise calculation. Then, FW-H equations are employed to calculate the aeroacoustic characteristics of isolated rotor, and G 1A formulas are applied to calculate the rotor acoustic gradient to provide boundary condition for acoustic scattering. Based on these, the time-domain equivalent source method is applied to calculate acoustic scatter field, and the total acoustic field that considered the fuselage scatter is superposed by isolated rotor acoustics and the scatter one. Finally, the numerical simulations of helicopter main-rotor/fuselage and tail-rotor/fuselage scatter effect are conducted by using the developed models. The results indicate that the helicopter fuselage has important scatter effect on the high frequency acoustics of main rotor and tail rotor, and the acoustic scatter effect become more obvious with the smaller space between the main rotor (tail rotor) and fuselage.
摘要
发展了直升机旋翼(尾桨)噪声与机身的声散射特性计算方法。首先,采用基于运动嵌套网格和RANS方程的旋翼CFD方法计算旋翼流场信息,为旋翼噪声计算提供气动数据;然后,采用FW-H方程来计算孤立旋翼的气动噪声特性,并应用G1A公式来计算旋翼噪声梯度,为噪声声散射分析提供边界条件;在此基础上,采用时域等效源方法计算散射声场,并与孤立旋翼声场进行叠加,最终得到考虑机身散射影响的总声场。最后,应用建立的声散射计算模型,针对旋翼/机身和尾桨/机身声散射效应进行了数值模拟,结果表明:机身对旋翼与尾桨高频噪声的散射影响较大,并且旋翼/机身以及尾桨/机身的间距越小,声散射效应越明显。
Key words: acoustic scatter / rotor / noise / fuselage / helicopter
关键字 : 声散射 / 旋翼 / 噪声 / 机身 / 直升机
© 2020 Journal of Northwestern Polytechnical University. All rights reserved.
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