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对某型民用飞机前起落架进行气动噪声进行数值仿真分析。采用分离涡模拟方法,计算起落架周围非定常湍流流场,提取声源信息,利用FW-H方程积分外推法求解模型辐射的声场,获得噪声的频谱特性及远场指向特性曲线。通过频谱对比,研究粗网格和细网格对仿真精度的影响以及不同积分面对噪声预测结果的影响。结果表明,分离涡模拟方法能够较好地模拟流场中存在的大量复杂的涡结构;当选取模型固体表面为积分面时,基于粗网格比基于细网格计算的声压级低约1dB;基于细网格定义空间可穿透面为积分面比定义模型固体表面为积分面计算的声压级高约5～7dB;起落架气动噪声源与其后部有规律的涡脱落相关,并且噪声辐射具有明显的指向特性。
The aerodynamic noise of front landing gear of a civil aircraft is numerically simulated. The discrete eddy simulation method is used to calculate the unsteady turbulent flow field around the landing gear, extract the sound source information, and use the integral extrapolation of the FW-H equation to solve the model radiation sound field to obtain the noise spectral characteristics and the far-field directional characteristic curve. Through spectrum comparison, the influence of coarse grid and fine grid on the simulation accuracy and the impact of different integrals on the noise prediction results are studied. The results show that the separation eddy simulation method can well simulate a large number of complex vortices existing in the flow field. When the solid surface of the model is selected as the integral surface, the sound pressure level based on the coarse grid is lower than that based on the fine grid by about 1dB ; Based on the definition of fine grid, the penetrable surface of the space is integral surface than the definition of the solid surface of the model for the integral surface of the calculated sound pressure level of about 5 ~ 7dB; landing gear aerodynamic noise source and its rear vortex shedding is related to the noise Radiation has obvious pointing characteristics.