• 流动特性分析 •

槽道内涡波流场展向涡的分布特征

1. 重庆工商大学 废油资源化技术与装备工程研究中心, 重庆 400067
• 收稿日期:2016-12-12 修回日期:2017-01-20 出版日期:2017-11-20 发布日期:2017-06-27
• 通讯作者: 陈彬 E-mail:hustchb@163.com
• 作者简介:陈彬,男,博士,教授。主要研究方向:流体动力学。
• 基金资助:
国家自然科学基金（51375516）；重庆市基础与前沿研究计划（cstc2016jcyjA0185）

Distribution characteristics of spanwise vortex of vortex wave field in channel flow

CHEN Bin, LIU Ge, JIN Xing, DENG Yangqin

1. Engineering Research Centre for Waste Oil Recovery Technology and Equipment, Chongqing Technology and Business University, Chongqing 400067, China
• Received:2016-12-12 Revised:2017-01-20 Online:2017-11-20 Published:2017-06-27
• Supported by:
National Natural Science Foundation of China (51375516); Chongqing Basic and Frontier Research Project (cstc2016jcyjA0185)

Abstract: The instantaneous velocity vector fields of the vortex wave field in the channel flow were measured by 2DPIV. The identification of the spanwise vortices is carried out by using the criteria of Reynolds decomposition and swirling strength λci criteria. The distribution characteristics of spanwise vortices are analyzed from scale properties, mechanical properties and motion properties of the counter-clockwise and clockwise vortices identified by swirling strength λci criteria. The results show that the number of clockwise vortices is larger than that of the counter-clockwise vortices in the flow field. The swirling strength of the counter-clockwise vortices is in the form of parabolic shape in the range of normal direction 0.05-0.45, while the clockwise vortices show the overall downward trend. And the average diameter and the long axis of the ellipse of the counter-clockwise vortices increase slowly with the increase of the normal position, while the clockwise vortex tends to decrease. The largest value of the inclination angle of the long axis of the ellipse of the counter-clockwise spanwise vortices is 67.28°. The eccentricity of the equivalent ellipse of the clockwise vortices shows a decreasing trend, and the circularity is better. The contribution of the counter-clockwise spanwise vortices to the total mean 〈z〉 has a maximum value of 61% at normal direction 0.15, and the contribution of the spanwise vortices to the total Reynolds stress is smaller; the population densities of counter-clockwise spanwise vortices in the 0-0.08 normal displacement range have a sharp upward trend, and achieve the maximum 0.36; The distribution of the clockwise spanwise vortices shows the inverted "U"-shape; The population density ratio of spanwise vortices with different directions of swirling to total spanwise vortices is greater than 0.3; the streamwise convective velocity of the spanwise vortices is less than that of the mean velocity of flow field in general, and the difference between them is larger in the central region of the channel. The normal convective velocity of the spanwise vortex increases from negative value to positive value with the increase of normal distance, and two phenomena of ejecting and sweeping occur on the two sides of the central mainstream.