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本文通过对直升机尾桨噪声的机理进行分析,建立了尾桨与涡线干扰噪声的计算模型。计算模型中包括气动计算和声学计算,气动计算的结果作为声学计算的输入量。气动计算中分别采用三维非定常面元法计算桨叶表面压力和有扰动薄翼理论计算涡线干扰下桨叶的压力增量;声学计算中采用推导自FW-H方程的Farassat1a公式,获得声压的时间历程。通过算例分析得到了一些有意义的结论。
In this paper, by analyzing the mechanism of helicopter tail rotor noise, a calculation model of tail rotor and vortex line noise is established. The calculation model includes both aerodynamic calculations and acoustic calculations. The aerodynamic calculation results are used as input to acoustic calculations. In the aerodynamic calculation, the blade surface pressure and the perturbed thin wing theory are respectively used to calculate the blade pressure increment under the vortex disturbances by using the three-dimensional unsteady face element method. In the acoustic calculation, the Farassat 1a formula derived from the FW-H equation is used to obtain the acoustic Pressure of the course of time. Through the example analysis, some meaningful conclusions are obtained.