机翼尾迹脱落涡噪声的理论研究

Ｍｉｃｈｅｌ等人１９９８年应用平面传声器阵列对飞机过顶噪声进行的测量研究首次发现，机翼尾迹脱落涡噪声是某些类型飞机重要的噪声源。为发展一种预测这种噪声源的理论预测模型，应用ｖｏｎ Ｋａｒｍａｎ涡街模型模拟二维机翼下游尾迹脱落涡，尾迹涡的强度和脱落频率应用这个模型进行计算。基于Ｈｏｗｅ后缘噪声理论，并结合尾迹模型，本文发展了一种预测脱落涡噪声声压级和指向特征的气动声学模型。对６架现代商用飞机的机翼尾迹脱落涡噪声的计算表明，本文理论模型预测的涡脱落频率、声压级以及噪声的指向性等与实验测量结果有较好的一致性。

Theoretical Investigation of the Vortex Shedding Noise from the Wake of Airfoil

The vortex shedding noise has been revealed as an important wing noise source on some modern commercial aircraft based on the fly-over measurements with a planar microphone array by Michel (1998). In this paper an analytical model is presented for predicting this vortex shedding noise. The downstream wake of a 2-dimensional airfoil is assumed to be dominated by the von Karman vortex street, and the strength and the shedding frequency of the wake vortex are determined from the wake structure model. An aero-acoustic model is developed based on the Howe's unified theory of trailing edge noise and is incorporated with the wake model to predict the sound pressure level and directivity of vortex shedding noise. The predicted vortex shedding frequencies, sound pressure levels and directivities compare favorably with the measured results for 6 modern commercial aircraft.