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建立了可用于直升机运动状态下噪声传播特性分析的高效地面声场预测方法。该方法包括计算旋翼气动、噪声的自由尾迹方法和时域FW-H方程;计入大气、地面等环境因素的声传播模型及地面声场计算模型;为提高计算效率,在声源计算与噪声传播之间引入基于“紧致球声源”的二级声辐射模型;在此基础上,还提出了通过建立“特征参数声辐射球库”以实现直升机运动状态下噪声实时预测的方法。以AH-1旋翼为算例,通过与地面声场直接计算法对比,说明了方法的有效性及高效性;此外,文中还分析了大气、地面等环境因素对噪声传播以及地面声场特性的影响。
An efficient method of predicting ground acoustic field can be used to analyze the characteristics of noise propagation under helicopter movement. The method includes calculating free-wake method of aerodynamic and noise of rotor and time-domain FW-H equation, calculating acoustic propagation model and surface acoustic field model based on environmental factors such as atmosphere and ground, and in order to improve computational efficiency in terms of sound source calculation and noise propagation Based on which the “second-order acoustic radiation model based on ” compact ball sound source “is introduced. Based on this, it is also proposed to realize the real-time prediction of noise under the helicopter movement by establishing the” characteristic parameter sound radiation ballroom " method. The AH-1 rotor is taken as an example to show the effectiveness and efficiency of the method by comparing with the direct calculation method of ground acoustic field. In addition, the influence of atmospheric and ground environmental factors on the noise propagation and ground acoustic field characteristics is also analyzed.