二维粒子图像测速实验中三维涡旋可测性分析

发布时间：2018-04-13 07:54

  本文选题：粒子图像测速 + 直接数值模拟　； 参考：《水科学进展》2017年05期

【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。
[Abstract]:Nowadays, two-dimensional particle image velocimetry (PIV) is widely used. In order to further improve the understanding of turbulence and the interaction mechanism of flow and sediment in PIV measurements, the measurability of three-dimensional vortices in two-dimensional PIV is analyzed.Combined with the rotation intensity method of vortex recognition, coordinate rotation theorem and turbulent classical Burgers vortex model, it is deduced that whether two-dimensional PIV can detect three-dimensional vortex is mainly affected by vortex loop quantity and inclination angle between vortex and measuring plane.The three-dimensional vortex can only be measured if the vortex loop is greater than a certain value (a function of inclination angle).The correlation curves and fitting equations of dip angle and ring volume under this condition are obtained by using the widely used direct numerical simulation of the channel turbulence data statistical analysis, and combined with the cumulative distribution of the probability density of the ring volume, it is known that in the conventional two-dimensional PIV experiment,The larger the probability of vortex is, the greater the angle of inclination is. The angle between the measured 3D vortex and the measured plane is 20 掳11 掳and 5 掳, respectively, with the probability of 90% and 10%.
【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;
【基金】：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)~~
【分类号】：TV149
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本文编号：1743588