亚音主旋翼的噪声预测和声隐身分析

本文介绍了基于FW-H方程的亚音主旋翼噪声预测方法,并在螺桨噪声预测程序基础上发展了主旋翼噪声预测程序。本文采用商用CFD软件FINE／TURBO模拟直升机旋翼流场,为噪声预测程序提供所需要的桨叶表面载荷,并用算例验证了载荷数据的准确性和噪声预测程序的有效性。本文计算和讨论了亚音悬停条件下的辐射噪声,并重点分析了不同形状桨叶对辐射噪声的影响,结果表明采用合理的薄翼型叶尖、尖削叶尖及线性扭转桨叶都可以降低辐射噪声,为通过改变桨叶形状降低旋翼辐射噪声提供了合理途径。

INVESTIGATION OF PREDICTING THE HELICOPTER MAIN SUBSONIC ROTOR NOISE IN HOVER

This paper presents a method to predict the main subsonic rotor noise of helicopter based on FW-H equation, and develops a prediction program from the propeller noise prediction program. The loads on the surface of blade used as the input of load noise prediction are obtained from CFD software. The paper presents some cases to check the veracity of the loadings and the validity of noise prediction program by comparing the calculation results with the data in references. This paper calculates the noise of subsonic rotor of helicopter in hover, and analyzes the influences of the blade geometry of rotor on the noise radiated by it. These calculations show that some benefit can be obtained by taking thin or twist or taper blade-tip shape in reducing the far-field noise which provide a reasonable ways to reduce rotor noise.