桨叶气动外形对直升机桨-涡干扰噪声影响研究

针对旋翼桨-涡干扰(Blade-vortex interaction,BVI)现象的复杂特征,建立了一个基于Navier-Stokes方程/自由尾迹模型的耦合欧拉-拉格朗日数值方法,用于干扰过程中脉冲气动载荷的计算。噪声的预测采用基于声学类比法的FW-H方程。应用上述方法以AH-1/OLS旋翼为研究对象,从"设计降噪"角度分析了具有后掠、前掠、尖削和下反桨尖形状旋翼的桨-涡干扰噪声特性。结果表明:目前直升机常采用的桨叶外形(尖削、后掠)对于降低桨-涡干扰噪声是有限的;而采用前掠、下反桨叶的旋翼具有较好的噪声隐身特性。

Research on Influence of Shape Parameters on Blade-Vortex Interaction Noise of Helicopter Rotor

A coupled Eulerian Lagrangian method based on Navier Stokes equation and free wake model is established for impulsive air loadings prediction during interaction. The noise prediction is based on the well known FW H equation for acoustic pressure. By the method, aiming at the noise abatement, a parametric study is performed to examine the effects of blade geometry parameters such as sweeptback,sweepforward,taper and anhedral tip on blade vortex interaction(BVI) noise of AH 1/OLS rotor. The results indicate that the BVI noise can be reduced by the blade geometry of anhedral tip and sweepforward, while the blade geometry (i.e. taper and sweepback) adopted by helicopter widely has finite influence on the reduction of BVI noise even the unfavourable influence.