Measuring three-dimensional flow structures in the conductive airways using 3D-PTV
Measuring three-dimensional flow structures in the conductive airways using 3D-PTV
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DOI：
10.1007/s00348-017-2407-x
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发表时间：
2017-10-01
影响因子：
2.4
通讯作者：
Bauer, Katrin
中科院分区：
文献类型：
--
作者：
Janke, Thomas;Schwarze, Ruediger;Bauer, Katrin
导电性气道中流动模式和质量运输的详细信息对于改善通气策略以及靶向药物递送至关重要。尽管在这一领域进行了大量的流动研究，但三维流动模式的实验数据仍然缺乏，特别是对数值结果的验证。因此，本文对人体上导气管真实模型内的振荡流动进行了实验研究。研究的雷诺数范围为Re = 250-2000，沃默斯利数在α = 1.9-5.1之间变化，其中包括静止状态下的生理流动。在采用三维粒子跟踪测速技术时，我们可以直接看到气道的特定流动结构，并检查拉格朗日轨迹统计，这是迄今为止尚未涉及的。特征流动参数的系统变化与先进的可视化技术相结合，为研究流型演变的机理提供了新的思路。通过确定拉格朗日性质，如路径曲率和扭转，我们发现两者都强烈依赖于雷诺数。此外，曲率的概率密度函数在某些流动区域显示出独特的形状，并且在小尺度上类似于湍流的行为。
Detailed information about flow patterns and mass transport in the conductive airways is of crucial interest to improve ventilation strategies as well as targeted drug delivery. Despite a vast number of flow studies in this field, there is still a dearth in experimental data of three-dimensional flow patterns, in particular for the validation of numerical results. Therefore, oscillating flow within a realistic model of the upper human conductive airways is studied here experimentally. The investigated range of Reynolds numbers is Re = 250-2000 and the Womersley number is varied between alpha = 1.9-5.1, whereby physiological flow at rest conditions is included. In employing the three-dimensional particle tracking velocimetry measurement technique, we can directly visualize airway specific flow structures as well as examine Lagrangian trajectory statistics, which has not been covered to date. The systematic variation of characteristic flow parameters in combination with the advanced visualization technique sheds new light on the mechanisms of evolving flow patterns. By determining Lagrangian properties such as pathline curvature and torsion, we find that both strongly depend on the Reynolds number. Moreover, the probability density function of the curvature reveals a unique shape for certain flow regions and resembles a turbulent like behavior at the small scales.