方腔流致振荡及噪声的数值研究

Numerical investigation of flow-induced oscillations and noise from a rectangular cavity

摘要: 采用直接数值模拟方法,研究了低Reynolds数下 L/D =2的方腔亚声速流致振荡现象及其诱导的噪声。结果表明,在所计算的参数范围内,振荡都是由Rossiter II模态主导;来流边界层变薄会导致低频成分的出现,其产生的直接原因是涡与后拐角撞击方式的切换,根源在于回流区与剪切层相互作用形式的不稳定。采用本征正交分解(POD)方法,分析了不同振荡形式所对应的本征模态涡结构及其与后拐角撞击方式的关系。计算得到并分析了声波的产生和传播过程,结果与已有实验结果和理论模型符合良好。

Abstract: In order to design the variable pitch of largescale wind turbine quickly and accurately, this paper applied the PSO algorithm to the aerodynamic pitch design and established the mathematical model of the design and calculation. With the 1.5MW large-scale wind turbine for pitch design calculation, the results show that the design calculation method proposed in this paper is feasible and practical.