Through the established re-circuiation water channel, the inner flow field in 90°bending duct of circular-section with a fore-end valve was measured by particle image velocime-try. Massive high-resolution data of transient flow field were obtained at different observation sections under diverse velocities. The transient and time-averaged flow fields after adaptive correlation calculation were analyzed. The POD modes were obtained after proper orthogonal decomposition of the flow fields, and the structural properties of vortex were further analyzed through the reconstruction of fluctuation field. Conclusions are drawn out that there exists Kdrmdn vortex street in the bend after the butterfly valve, the vortex information is included in low proper orthogonal decomposition modes, and the flow properties of vortex can be restored through the reconstruction of fluctuation field.%利用激光粒子图像测速技术对阀体后90°圆截面弯管的内部流场进行测量,获取了弯管流场在不同来流流速及观测截面上的高分辨率瞬态速度场数据.分析了图像相关计算所获得的瞬态及时均速度场,对流场进行本征正交分解,并进一步分析重构脉动场中的涡结构特性.结果表明:流体流经蝶阀在弯管中形成卡门涡街,涡结构信息包含在本征正交分解低阶模态中,脉动场的模态重构可以还原涡的流动特性.
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