对某型飞机主起落架结构件的气动噪声特性进行了声学风洞试验和数值仿真分析.在声学风洞中,借助麦克风测量获得不同来流速度下噪声频谱特性.采用分离涡方法仿真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,利用FW-H方程积分外推法求解声场,分析噪声的频谱特性、远场指向特性及其产生的机制.结果表明:起落架结构件噪声频谱特性仿真结果与试验结果在低频和中频段吻合较好；起落架结构件噪声呈现宽频噪声的特性；频谱曲线以及频谱中优势频率均随着来流速度的增加而增大；仿真曲线中的能量峰值分别对应于缓冲器与支柱、缓冲器与摇臂的干扰噪声；形成此噪声源的压力脉动位于缓冲器下部表面区域；缓冲器和摇臂是总噪声的主要贡献源,支柱对总噪声的贡献量最小；噪声辐射呈现非对称的指向特性.%Aeroacoustic wind tunnel tests and simulation analysis were performed for aerodynamic noise characteristics of an aircraft's main landing gear component. The sound field radiated from the structure was measured in an aeroacoustic wind tunnel at different wind speeds. The noise spectra were evaluated with micro-phones. Detached eddy simulation was used to build a flow field around the structure. The sound source strength and location were calculated with the vortex sound theory. The acoustic field was calculated via FW-H equation. The frequency spectra, the directivity characteristics and its mechanism of the noise were subsequently studied. The results indicated that the spectra in lower and middle frequency ranges from the simulation agree with those from the tests; the noise radiated around the structure is a broadband noise; the spectra and dominant frequencies increase with increase in wind speed; in the spectra, there are two energy peaks corresponding to the inter-action noises between shock absorber and strut as well as shock absorber and bogie, respectively; the pressure fluctuation forming the noise sources is on the surface of the lower part of the shock absorber; the shock absorber and bogie are the main contributors while the strut is the least contributor to the total noise; noise radiation has unsymmetric directivities.
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