The level of noise emission of a circular cylinder, especially a tower of a wind turbine, is remarkably dependent on vortex shedding behind the body of the tower. For these configurations, the key element to reduce noise emission is the upstream flow control of the body. In this paper, the sound pressure level of a wind turbine tower was investigated numerically. In this regard, an in-house OpenFoam solver with Curle’s acoustic analogy was used, and the results were compared with available experimental data, showing proper consistency among them. Then, three passive control methods such as longitudinal slot, splitter plate, and helical strake were applied to control the Kármán vortex shedding behind the tower, followed by the reduction in the level of sound pressure. The results showed that all the above control methods play an essential role in diminishing the fluctuation forces and affect the frequency of vortex shedding. However, the helical strake can lead to the significant suppression of Kármán vortex shedding due to the delay of boundary layer flow separation. Based on the observations, the tower with helical strake reduced the overall level of sound pressure as well as the Aeolian tones in a specific Strouhal number range.

中文翻译：

---

大型风力涡轮机塔筒涡流脱落结构和声压级的数学建模

圆柱体，尤其是风力涡轮机的塔架的噪声排放水平显着依赖于塔体后面的涡流脱落。对于这些配置，减少噪音排放的关键因素是车身的上游流量控制。在本文中，对风力涡轮机塔架的声压级进行了数值研究。在这方面，使用了具有 Curle 声学类比的内部 OpenFoam 求解器，并将结果与​​可用的实验数据进行了比较，显示了它们之间的适当一致性。然后，采用纵向槽、分隔板和螺旋板条等三种被动控制方法来控制塔后的卡门涡脱落，进而降低声压级。结果表明，上述所有控制方法在减小波动力和影响涡旋脱落频率方面都起着至关重要的作用。然而，由于边界层流动分离的延迟，螺旋条带会导致卡门涡旋脱落的显着抑制。根据观察结果，带有螺旋边条的塔降低了整体声压水平以及特定斯特鲁哈尔数范围内的风神音调。