节径凸起结构对串列双圆柱干涉噪声的影响

为探究周期性节径凸起结构对串列双圆柱体钝体杆件干涉噪声的降噪效果与降噪规律，在0.55 m×0.4 m声学消声风洞开展了串列双圆柱降噪实验，设计了8种不同参数的周期性节径凸起结构，实验研究了4种不同来流速度(雷诺数为0.4×10⁵～1.6×10⁵)下周期性节径凸起结构对串列双圆柱干涉噪声的影响。研究表明：周期性节径凸起结构可以减弱甚至完全抑制单音峰值噪声的产生，最大峰值噪声降噪量可达近30 dB，总声压级最高降噪量可达18.1 dB。不同工况状态下，各种参数化结构对噪声抑制能力有所不同，均存在最佳值，其中凸起高度为(0.1D～0.15D)、凸起间距为0.5D左右(D为基准圆柱直径)的周期性节径凸起结构在较广工况范围下都具有较好的降噪效果。周期性节径凸起结构的引入，不仅改变了串列双圆柱对应的峰值特征频率和涡脱落频率，而且抑制圆柱杆件卡门涡街的产生。

Influence of pitch diameter protruding structure on interference noise of tandem double cylinders

In order to explore the noise reduction effect and noise reduction law of the periodic pitch diameter protruding structure on the interference noise of the tandem double cylinders bluff body, noise reduction experiments of tandem double cylinders were carried out in the 0.55 m×0.4 m anechoic wind tunnel. Eight kinds of periodic pitch diameter protruding structures with different parameters were designed, and the noise reduction effects of pitch diameter periodic protruding structure on the interference noise of the tandem double cylinders were tested at four incoming flow velocities (Reynolds number 0.4×105?1.6×105). Experiment results showed that, the tone peak noise can be reduced or even be completely suppressed by the periodic pitch diameter protruding structure. The maximum peak noise reduction can reach nearly 30 dB, and the maximum overall sound pressure level noise reduction can reach 18.1 dB. Under different working conditions, different structures had different noise suppression capability and there was an optimal value for each working condition. Generally speaking, periodic pitch diameter protruding structure with protruding height of (0.1D～0.15D), protruding space of 0.5D has the best noise reduction effect across a wide working condition range. The introduction of periodic pitch diameter protruding structure not only changed the peak characteristic frequency and vortex shedding frequency of tandem double cylinders, but also suppressed the generation of Karman vortex street.