旋翼干扰下的直升机尾桨气动噪声计算研究

针对旋翼干扰下的直升机尾桨气动噪声计算问题,将CFD方法与Farassat 1A(F1A)公式相结合,提出了一种适用于旋翼干扰下的尾桨气动噪声数值计算方法。首先,应用所提出的方法进行了噪声的算例验证,并与参考文献结果进行了对比;然后,着重针对悬停和前飞状态旋翼干扰下的尾桨噪声及气动特性进行了计算分析,并与孤立尾桨状态进行了对比。计算分析结果表明:悬停状态下,旋翼干扰下的尾桨气动噪声水平显著大于孤立尾桨;而在前飞状态,由于旋翼尾迹对尾桨桨盘平面产生更强的气动干扰,这一现象会更加明显;同时,在旋翼干扰作用下,尾桨噪声的主传播方向也会发生明显变化。

Computational research on helicopter tail rotor aerodynamic noise under the main rotor interaction

For the calculation of helicopter tail rotor aerodynamic noise under the rotor interaction, the CFD method was combined with the Farassat 1 A(F1 A) formula, and a numerical calculation method suitable for tail rotor aerodynamic noise under the rotor interaction was proposed. Noise examples was verified firstly, and the results were compared with the data of the reference. Then, aerodynamic and acoustic characteristics of tail rotor under the rotor interaction were emphatically calculated in both hover and forward flight. Also, comparisons with isolated tail rotor were done. The calculation and analysis results show that, in hovering state, the aerodynamic noise level of the tail rotor under the rotor interaction is significantly greater than that of the isolated tail rotor. While in the forward flight state, the rotor wake produces stronger aerodynamic interaction to the plane of the tail rotor blade, so the phenomenon will be more obvious. At the same time, under the rotor interaction, the main propagation direction of the tail rotor noise will also change significantly.