机体表面湍流边界层噪声特性及预测方法研究

湍流边界层噪声是飞机巡航过程中的主要外部噪声源,对舱内噪声水平的影响尤为重要。因此,对飞机机体表面湍流边界层噪声的研究具有重要意义。本文通过试验获得了某型民机巡航过程中的湍流边界层噪声,试飞工况为3500ft/0.78、3500ft/0.7、2500ft/0.67、1500ft/0.66。对实测数据进行分析,发现湍流边界层噪声与动压、边界层厚度等参数有关。同时,利用计算流体力学的方法得到了飞机机体表面的压力分布,并分析了压力梯度对湍流边界层噪声的影响。最后,基于工程预测方法对湍流边界层噪声进行了预测,对于不存在逆压梯度的区域,预测结果与试验结果吻合较好,仅部分频段存在一定偏差。通过对模型的参数进行优化,改善了预测结果。

Study on turbulent boundary layer noise characteristics and prediction method on the airframe surface

Turbulent boundary layer noise is the main external noise source during aircraft cruise, which has a particularly important impact on the noise level in the cabin. Therefore, it is of great significance to study the turbulent boundary layer noise on the airframe surface. In this paper, the turbulent boundary layer noise of a civil aircraft during cruise is obtained experimentally. The flight test conditions are 3500ft / 0.78, 3500ft / 0.7, 2500ft / 0.67 and 1500ft / 0.66. By analyzing the measured data, it is found that the turbulent boundary layer noise is related to parameters such as dynamic pressure and boundary layer thickness. At the same time, the pressure distribution on the aircraft body surface is obtained by using the method of computational fluid dynamics, and the influence of pressure gradient on turbulent boundary layer noise is analyzed. Finally, the turbulent boundary layer noise is predicted based on the engineering prediction method. For the region where there is no inverse pressure gradient, the prediction results are in good agreement with the experimental results, and there is a certain deviation in some frequency bands. By optimizing the parameters of the model, the prediction results are improved.