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对某型飞机前起落架的气动噪声特性进行了数值仿真分析和声学风洞试验研究。在典型飞机着陆速度下,采用分离涡(DES)方法模拟起落架周围非定常湍流流场,通过涡声理论计算声源的强度和位置,并利用FW-H(Ffowcs-Williams/Hawkings)方程积分外推法求解出不同部件及其组合件产生的声场,分析其噪声的产生机制、频谱特性及远场指向特性,同时评估各部件对总噪声的贡献量。在声学风洞中对轮胎和轮叉组合件进行气动声学试验,借助麦克风测量获得了噪声的频谱特性。基于部件固体表面积分计算的仿真结果与试验结果在声学远场条件下吻合较好。仿真结果表明:起落架气动噪声是钝体绕流噪声和空腔噪声的叠加,呈现宽频噪声的特性。强度最大的声源主要分布在起落架各部件的固体表面;轮胎噪声对总噪声的贡献最大,其次是轮叉噪声,支柱噪声对总噪声贡献最小。各部件噪声和总噪声均具有偶极子声源的辐射特性。空间可穿透积分面计算的声压级结果比固体表面计算的声压级结果大5dB左右。该研究结果为低噪声起落架设计提供了一定的参考。
The aerodynamic noise characteristics of nose landing gear of a certain type of aircraft are numerically simulated and studied by acoustic wind tunnel test. Under typical aircraft landing speed, the separation vortex (DES) method is used to simulate the unsteady turbulent flow field around the landing gear, the intensity and position of the sound source are calculated by the vortex theory, and the FW-H (Ffowcs-Williams / Hawkings) The extrapolation method solves the sound field generated by different components and their assemblies, analyzes the noise generation mechanism, spectral characteristics and far-field directional characteristics, and simultaneously evaluates the contribution of each component to the total noise. Aerodynamic acoustic tests were performed on the tire and fork assembly in the acoustic wind tunnel and the spectral characteristics of the noise were measured with the aid of a microphone. The simulation results based on component solid surface integral calculation agree well with the experimental results under the acoustic far field conditions. The simulation results show that the landing gear aerodynamic noise is a combination of bluff body flow noise and cavity noise, presenting the characteristics of wideband noise. The most intense sound sources are mainly distributed on the solid surfaces of the landing gear components. The tire noise contributes the most to the total noise, followed by the fork noise, while the pillar noise contributes the least to the total noise. The noise of each component and the total noise have the radiation characteristics of the dipole sound source. The sound pressure level results of the space penetrable integral surface calculation are about 5 dB greater than the sound pressure level results calculated on the solid surface. The results of this study provide a reference for the design of low noise landing gear.