斜下降旋翼桨涡干扰声源定位及表面压力

旋翼桨-涡干扰（BVI）是直升机在进场和离场等近地飞行时后行桨叶切割前行桨叶脱落桨尖涡产生的气动扰动，该扰动不仅对桨叶表面压力载荷产生激励作用，同时也会引起旋翼噪声出现激增，旋翼噪声激增的主要成分为桨-涡干扰噪声。本文首先对斜下降桨-涡干扰状态桨叶表面载荷进行数值计算；然后分别阐述了基于改进整周期同步平均旋翼噪声去噪方法、基于多层小波包分解的桨-涡干扰声源识别和分离方法以及基于bartlett时延计算和球面插值的声源定位方法，设计并开展了风洞斜下降状态桨-涡干扰桨叶表面压力和声源定位试验，给出了开发的声源定位软件界面、声源定位图像畸变校准方法及声阵列现场校准方法；最后对比分析了不同试验状态的桨-涡干扰噪声声源特性以及和桨叶表面压力之间的关联性，并给出了声源定位及表面压力试验数据分析结果。结果表明典型斜下降状态后行侧桨-涡干扰主要出现在方位角310°~330°、径向位置1.6~1.8 m桨盘平面区域。

Rotor blade-vortex interaction noise location and surface pressure in skew descending flight

Rotor Blade-Vortex Interaction (BVI) is the aerodynamic disturbance caused by rotors of the retreading side cutting the shedding vortex of the advancing side blade during the approach and departure of helicopters. Apart from exciting the blade surface pressure load, the interactions also sharply increase the rotor noise predominated by the BVI noise. This article first presents the numerical simulation of the rotor BVI load, followed by elaboration of the denoising method based on the period time synchronous averaging, the recognition and separation approach of the BVI noise from the rotor noise using wavelet decomposition reconstruction, and the noise location method based on bartlett time delay calculation and spherical interpolation. A rotor blade-vortex interaction noise test in the wind tunnel is designed and completed to verify these methods. We also develop the software applied to rotor BVI noise location and surface pressure test in skew descending flight status, and the research of the temporal and spatial relationship between the rotor BVI noise and blade surface pressure load. The main software interfaces, the vibration measurement system, and the modification method of noise source location aberrations are presented. The test results indicate that the rotor blade vortex interaction on the rotor disk mainly appears at the section of 310°-320° azimuth and 1.6-1.8 m radial position.