缝翼结构参数对翼型流场和气动噪声的影响

缝翼气动噪声很大程度地依赖于其结构参数。分析其结构参数对翼型流场及其气动噪声特性的影响,是研究缝翼噪声抑制方法的有效途径。首先,基于典型三段翼型30P-30N,建立流场分析模型,并利用雷诺平均(RANS)和大涡模拟(LES)方法,分别对具有典型缝翼几何位置及外形特征的翼型进行稳态和瞬态流场特性分析;其次,利用FW-H声类比积分法求解远场噪声分布特性,并研究对比不同缝翼结构参数对远场声压级强度及其指向性分布特性的影响规律;最后,针对不同的缝翼结构参数,分析讨论缝翼噪声抑制与相应翼型升力变化的耦合关系。结果表明:缝翼几何位置和结构变形参数的调整均可有效降低远场噪声辐射,但是在攻角增大的情况下升力系数会有一定程度的降低。

Effects of Slat Parameters on Features of Flow and Noise for an Airfoil

Slat noise is largely dependent on its structure parameters which are geometry and morphing parameters. The investigation of the effects of these two parameters on the features of flow and noise for an airfoil is an effective method of developing techniques for the slat noise suppression. Firstly, Three-element airfoil model 30P-30N is employed to establish the model of investigation for analyzing the flow and noise features. Based on RANS and LES methods, steady and unsteady characteristics of the airfoil flow are studied for typical geometric (overlap, gap and rotation angle)and morphed profiles (morphed tailing edge of slat seals the gap). Then the corresponding distributions of pressure and turbulent kinetic energy are obtained. Secondly, FW-H acoustic analogy formulation is employed to solve the far-field noise radiation for the slat. The inter-relationship of various slat structure parameters with the far-field acoustic pressure level and its directivity features are investigated. Finally, based on various slat structure parameters and their flow and noise characteristics obtained, the interaction of slat noise attenuation and its corresponding lift changes are analyzed and discussed. The results show that the slat geometry and structural deformation parameters can effectively reduce far-field noise radiation, but the lift coefficient will be reduced to some extent when the angle of attack increases.