基于无限元方法的直升机外部噪声仿真分析

Simulation Analysis of Helicopter Exterior Noise Based on Infinite Element Method

为了准确地模拟直升机飞行中的外部噪声,建立了耦合计算流体力学/计算气动声学(Computational fluid dynamics/Computational aeroacoustics,CFD/CAA)的直升机机外噪声预测方法。气动计算采用CFD方法模拟旋翼、尾桨气动力以及气动干扰;噪声计算采用声学无限元方法,考虑固体边界的声散射效应和大气传播中的声衰减特性。以AC311A直升机为例,开展适航规范要求下的飞越噪声计算和分析。飞行试验结果对比分析验证了本文方法能够有效地用于直升机机外噪声的评估与分析。最后进行了误差分析,为直升机外部噪声评估算法和仿真模型的优化提供参考。

In order to accurately simulate the external noise of helicopter in over flight,a coupled computational fluid dynamics/computational aeroacoustics(CFD/CAA)model is established.CFD method is used to simulate the aerodynamic force and aerodynamic interference of rotor and tail rotor in aerodynamic calculation.Acoustic infinite element method is used in noise calculation,considering the sound scattering effect of solid boundary and the sound attenuation characteristics in atmospheric propagation.On this basis,taking AC311A helicopter as an example,the calculation and analysis of over flight noise under airworthiness specifications are carried out.Combined with the comparative analysis of flight test results,it is verified that the method established in this paper can be effectively used for the evaluation and analysis of helicopter external noise.Finally,the error analysis is carried out to provide reference for the optimization of external noise evaluation algorithm and simulation model.