不可压缩旋转涡对的流噪声计算研究

相隔一定距离的两个同向旋涡相互诱导而形成绕中点旋转的涡对,进而诱发流噪声。该文基于不可压缩流场提供的非稳态流动信息,采用黏声分离法研究水流场中旋转涡对的声学特性。计算结果同理论值进行比较,并探讨了计算条件对计算稳定性和准确性的影响。计算结果表明:在选取合适的计算参数(人工阻尼、网格尺寸和时间步长)的情况下,黏声分离法方法适用于预测水流噪声。对不可压缩旋转涡对的声场特性进行分析,得到旋转涡对声压图案类似四极子,在远场接近圆柱波;随着旋转马赫数的增加,声压级增大。

Numerical study of flow noise from an incompressible co-rotating vortex pair

Two vortices of same direction at intervals form the vortex pair rotating around the midpoint,and then induce flow noise.Based on the information of unsteady incompressible flow field,the paper investigates the acoustic characteristics of co-rotating vortex pair using viscous acoustic splitting method in the flow field.The calculated results are compared with the theoretical ones,and the influence of the calculation conditions on the stability and accuracy of the calculation is discussed in details.It is shown that viscous acoustic splitting method is suitable for predicting the flow noise with appropriate calculated parameters (artificial damping,meshing size and time step).Analyzing the characteristics of acoustic field on an incompressible co-rotating vortex pair,it turns out that the acoustic pressure pattern of a vortex pair is similar to a quadrupole source and the acoustic wave is nearly cylindrical in the far field.The sound pressure level increases with the rising rotating Mach number.