旋转点声源声场的数值仿真计算

旋转声源辐射声场的计算是利用点源模型预测风扇离散噪声的关键所在,对叶片式机械气动噪声的研究具有重要参考价值.提供了在任意边界条件下计算旋转点声源辐射卢场的数值仿真计算方法.将连续的旋转声源离散化,处理为分布于旋转轨迹上的有限个固定点声源.利用离散化处理后的声源,通过边界元法分别计算旋转单极子和旋转点力源的辐射声场.在自由空间内的计算结果与理论解进行了对比验证,得到较为理想的结果:另外进行了有限长圆管内旋转点声源辐射声场的数值计算,由此对不同长度圆管的结果进行对比,分析了管道长度对声场分布以及指向性的影响规律.

Numerical simulation of rotating point source

The calculation of rotating sound source is the key to forecasting fan rotational noise by using point-source model, it has an important reference value for the study of the aerodynamic noise generating from blade fluid machinery. A numerical simulation method which can calculate the sound field of rotating point source at arbitrary boundary conditions is provided: Transform continuous rotating point source into finite discrete sources distributing along the rotating trace, and then calculate the sound field of rotating spherical source and rotating point force respectively by using the boundary element method. Comparing the theoretical solution with numerical solution in free space, we can get comparatively perfect result. The sound field of rotating point force in a finite-length round duct is calculated. And the comparison between the results of different duct lengths and the analysis of the influence of duct length change on sound field distribution and directivity are made.