| 二维粒子图像测速实验中三维涡旋可测性分析 |
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| 引用本文： | 陈槐,朱立俊,范红霞,王建中,王志寰.二维粒子图像测速实验中三维涡旋可测性分析[J].水科学进展,2017,28(5):738-744. |
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| 作者姓名： | 陈槐 朱立俊 范红霞 王建中 王志寰 |
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| 作者单位： | 南京水利科学研究院水文水资源与水利工程科学国家重点实验室, 江苏 南京 210029 |
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| 基金项目： | 国家自然科学基金资助项目（51609146）；南京水利科学研究院青年基金资助项目（Y216008） |
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| 摘 要： | 现今二维粒子图像测速（PIV）广泛应用，为进一步提高PIV测量结果对紊流及水流和泥沙相互作用机理的理解，分析了二维PIV中三维涡旋的可测性。结合涡旋识别的旋转强度方法、坐标旋转定理和紊流经典Burgers涡模型，推导得出:二维PIV能否检测出三维涡旋，主要受涡旋环量和旋涡与测量平面之间的倾角两个因素影响，且仅当涡旋环量大于某一特定值（为倾角的函数）时，三维涡旋才可以被测量出。利用广泛使用的直接数值模拟（DNS）槽道紊流数据统计分析，得出了该条件下倾角和环量的相关曲线与拟合方程；结合环量概率密度累积分布可知，在常规二维PIV实验中，涡旋被测量出的概率越大，相应的倾角也越大，其中以90%、50%和10%的概率被测量出的三维涡旋与测量平面间分别呈20°、11°和5°的倾角。
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| 关 键 词： | 粒子图像测速 直接数值模拟 涡旋 旋转强度 Burgers涡 倾角 环量 |
| 收稿时间： | 2017-03-25 |
Detection of 3-D vortex in the 2-D PIV experiment:analytical solution and application |
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| CHEN Huai,ZHU Lijun,FAN Hongxia,WANG Jianzhong,WANG Zhihuan.Detection of 3-D vortex in the 2-D PIV experiment:analytical solution and application[J].Advances in Water Science,2017,28(5):738-744. |
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| Authors: | CHEN Huai ZHU Lijun FAN Hongxia WANG Jianzhong WANG Zhihuan |
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| Affiliation: | State Key Laboratory of Hydrology, Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing 210029, China |
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| Abstract: | Nowadays the 2-D PIV is widely used in the field of fluid velocimetry. The study of characteristics of 3-D vortices detected in the 2-D PIV experiment is helpful to deeply analyze measured data and further know the fundamental turbulent physics and the fluid-particle interaction. Based on the vortex identification scheme (the swirling strength criterion), the Euler's rotation theorem and the Burgers vortex model, analytic solutions for the detection of 3-D vortex in the 2-D PIV experiment are derived. The solution demonstrates that two factors (the elevation angle made by the 3-D vortex with the measurement plane and the circulation of the vortex) influence the detection and only when the circulation value is greater than a specified value (a function of the elevation angle), the 3-D vortex could be detected. The direct numerical simulation (DNS) data of fully developed turbulent channel flow is used for the statistical analysis of that detection condition. Results show that in the 2-D PIV experiment, the higher the detection probability is, the larger the elevation angle will be. For examples, 3-D vortex tubes with detection probabilities of 90%, 50% and 10% have elevation angles of 20°, 11° and 5° respectively. |
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| Keywords: | particle image velocimetry direct numerical simulation vortex swirling strength Burgers vortex model elevation angle circulation |
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