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μ-PIV measurements of the ensemble flow fields surrounding a migrating semi-infinite bubble
Experiments in Fluids ( IF 2.4 ) Pub Date : 2009-04-26 , DOI: 10.1007/s00348-009-0662-1
Eiichiro Yamaguchi 1 , Bradford J Smith , Donald P Gaver
Affiliation  

Microscale particle image velocimetry measurements of ensemble flow fields surrounding a steadily migrating semi-infinite bubble through the novel adaptation of a computer controlled linear motor flow control system. The system was programmed to generate a square wave velocity input in order to produce accurate constant bubble propagation repeatedly and effectively through a fused glass capillary tube. We present a novel technique for re-positioning of the coordinate axis to the bubble tip frame of reference in each instantaneous field through the analysis of the sudden change of standard deviation of centerline velocity profiles across the bubble interface. Ensemble averages were then computed in this bubble tip frame of reference. Combined fluid systems of water/air, glycerol/air, and glycerol/Si-oil were used to investigate flows comparable to computational simulations described in Smith and Gaver III (J Fluid Mech 601:1–23, 2008) and to past experimental observations of interfacial shape. Fluorescent particle images were also analyzed to measure the residual film thickness trailing behind the bubble. The flow fields and film thickness agree very well with the computational simulations as well as existing experimental and analytical results. Particle accumulation and migration associated with the flow patterns near the bubble tip after long experimental durations are discussed as potential sources of error in the experimental method.

中文翻译:

围绕迁移的半无限气泡的整体流场的 μ-PIV 测量

通过计算机控制的线性电机流量控制系统的新颖适应,对稳定迁移的半无限气泡周围的整体流场进行微尺度粒子图像测速测量。该系统被编程为产生方波速度输入,以便通过熔融玻璃毛细管反复有效地产生准确的恒定气泡传播。我们提出了一种新技术,通过分析气泡界面上中心线速度剖面标准偏差的突然变化,在每个瞬时场中将坐标轴重新定位到气泡尖端参考系。然后在此气泡尖端参考系中计算整体平均值。水/空气、甘油/空气的组合流体系统,和甘油/硅油用于研究与 Smith 和 Gaver III (J Fluid Mech 601:1–23, 2008) 中描述的计算模拟相当的流动,以及过去对界面形状的实验观察。还分析了荧光颗粒图像以测量气泡后面的残留膜厚度。流场和薄膜厚度与计算模拟以及现有的实验和分析结果非常吻合。在长时间的实验持续时间后,与气泡尖端附近的流动模式相关的粒子积累和迁移被讨论为实验方法中的潜在误差来源。还分析了荧光颗粒图像以测量气泡后面的残余膜厚度。流场和薄膜厚度与计算模拟以及现有的实验和分析结果非常吻合。在长时间的实验持续时间后,与气泡尖端附近的流动模式相关的粒子积累和迁移被讨论为实验方法中的潜在误差来源。还分析了荧光颗粒图像以测量气泡后面的残留膜厚度。流场和薄膜厚度与计算模拟以及现有的实验和分析结果非常吻合。在长时间的实验持续时间后,与气泡尖端附近的流动模式相关的粒子积累和迁移被讨论为实验方法中的潜在误差来源。
更新日期:2009-04-26
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