槽道流POD重构及湍流动能耗散率分析

Anslysis of Kinetic Energy Dissipation Rate and POD Reconstruction of a Channel Flow

  • 摘要: 采用二维粒子图像测速仪(2DPIV)对槽道内涡波流场进行实验研究,用POD技术对2DPIV瞬态速度矢量场进行主导模态重构,得到槽道内的平均流速和湍流动能分布;采用大涡PIV方法对湍流动能耗散率分布进行计算.结果表明:重构流场表征了原始流场的主导结构,剔除了噪声等干扰信息;大涡PIV方法能有效地估算动能耗散率的分布;湍流动能在壁面附近较小,在接近槽道中心区域湍流动能越来越大,呈现出射流的特征;动能耗散率的峰值出现在壁面附近和槽道中心区域,动能耗散率随着远离壁面程度的增加先降低后逐渐增加直至达到峰值.

     

    Abstract: Vortex wave flow field within a channel was measured using particle image velocimetry (2DPIV). Instantaneous velocity vector field measured was reconstructed with dominant modes using POD technology. Average velocity and turbulent kinetic energy distribution were obtained using POD reconstructed field. Turbulent kinetic energy dissipation rate was estimated by using a large eddy PIV method. It shows that dominated structure of original flow field were characterized by reconstruction of flow field. Noise and other interference information were eliminated. Large eddy PIV method estimates effectively distribution of kinetic energy dissipation rate. Turbulent kinetic energy is small in vicinity of wall. Turbulent kinetic energy increases near center of channel region, which is characteristics of jet. Kinetic energy dissipation rate peak appears in vicinity of central region and channel wall. Away from wall kinetic energy dissipation rate is increases initially, and decreased gradually until it reaches a peak.

     

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