流致噪声机理及预报方法研究综述

从自由湍流噪声、壁面湍流噪声、转子噪声和空腔流动4 个方面对流致噪声机理及预报方法进行综述。对目前工程应用中的3个主要流致噪声预报方法,即Lighthill声比拟理论、Kirchhoff方法和涡声理论的基本原理及适用性进行详细讨论,并对流致噪声数值模拟方法进行总结。其中,Lighthill声比拟理论属噪声源先验理论,虽方便应用但不能描述声流相互作用基础问题;Kirchhoff方法在运用的过程中虽不需要确切获知源的属性,但声源区的计算精度很重要;涡声理论在声流相互作用等领域有着良好的研究前景。自由湍流噪声以四极子雷诺应力源为主,存在如螺旋桨等固壁边界时则会产生偶极子源,在低马赫数流动中是更为有效的声源。

A comprehensive review on the mechanism of flow-induced noise and related prediction methods

In this paper, a comprehensive review is presented on the mechanism of flow-induced noise and the related prediction methods. The review consists of four aspects: noise of submerged jets, Turbulent Boundary Layer(TBL)noise, rotor noise, and flow over cavities. The mechanism and applicability of noise prediction in the field of engineering using Lighthill acoustic analogy, Kirchhoff formulation, and the theory of vortex sound are explained in detail. Furthermore, numerical simulation methods of flow-induced noise are summarized. Specifically, Lighthill acoustic analogy presumes the noise source to be known in advance, which simplifies its engineering practice; nevertheless, it is defective to describe the exact interaction be-tween flow and sound. Meanwhile, any sound field could be calculated through Kirchhoff approach without source details, but the calculation in the near-field region directly affects the overall precision of the noise field. Finally, profound research on the interaction between vortex and potential flow indicates that the theo-ry is promising when it comes to the production and transformation of acoustic energy. In this case, free field flow noise is presented in quadruple form, while it is presented in dipole form when hard wall bound-ary exists including operating screws, which serves as a much more effective sound source.