不同飞行状态下施翼与大气湍流的干扰噪声

本文简述了一种直升机旋翼与大气湍流入流相干扰产生的噪声预估方法。这一方法考虑了桨叶上非定常载荷的弦向及展向非紧致性，桨叶－桨叶载荷之间的相关，通过结合大气湍流能量谱模型与快速畸变湍流收缩模型来确定旋翼平面处非均匀、各向异性湍流场的特性，使得这种方法可用于直升机在真实飞行状态下的旋翼与湍流场干扰噪声计算。利用文献中模型旋翼试验的结果，验证了本方法的可行性，并计算了某型直升机在六种飞行状态下的流场畸变情况及旋翼与湍流干扰的远场噪声谱，结果表明：在准悬停及低速爬升状态，湍流场的畸变较大，而在中、快速前飞状态，湍流场的畸变最小，在低速爬升状态，线性总声压级最小。

Rotor Noise Due to Ingestion of Atmospheric Turbulence in Varied Flight Status

An analytical prediction method for helicopter rotor noise due to the ingestion of atmospheric turbulence is summarized.The method used here has accounted for the chordwise and spanwise noncompactness effects of blade surface pressure, and the blade-to-blade loading correlations. This method can be used to calculate absolute noise leyels for full scale helicopter in realistic flight conditions by incorporating an atmospheric turbulence model and a rapid distortion turbulence contraction model which together determine the statistics of the non-isotropic and non-homogeneous turbulence at the rotor plan. The predicted turbulence ingestion noise levels are compared with the model rotor experimental results of a reference, and a good agreement is obtained. The distortion of turbulence field and the resulting noise spectra are calculated for six flight conditions of a helicopter, and it is found:(1)the distortions of turbulence for pseudo-hover case and low speed vertical ascent case are more severe ;(2) there is little distortion in the middle forward flight easel (3) in the low speed vertical ascent case, the overall SPL is the lowest.