湍流边界层中光滑表面和超疏水表面上的均匀动量区  

Uniform momentum zones on the smooth and superhydrophobic surfaces in a turbulent boundary layer

作　　者：王宇飞 黄逸军 张津浩 田海平 姜楠 Yu-Fei Wang;Yi-Jun Huang;Jin-Hao Zhang;Hai-Ping Tian;Nan Jiang(School of Mechanical Engineering,Tianjin University,Tianjin 300354,China;National Demonstration Center for Experimental Mechanics Education,Taiyuan University of Technology,Taiyuan 030024,China;Tianjin Key Laboratory of Modern Engineering Mechanics,Tianjin 300354,China)

机构地区：[1]不详

出　　处：《Acta Mechanica Sinica》2023年第8期25-41,共17页力学学报（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(Grant Nos.11972251,11902218,12172242,12272265,12202310);Chinesisch-Deutsche Zentrum fir Wissenschafisforderung(Grant No.GZ1575);China Postdoctoral Science Foundation(Grant No.2022M712357);the Young Scientists Fund of the National Natural Science Foundation of China(Grant No.11802195).

摘　　要：在Re_(τ)=528的湍流边界层中使用时间分辨的二维PIV研究了光滑表面和超疏水表面上的等动量区. 通过局部动能亏损率检测了湍流/非湍流界面, 随后在瞬时速度场中通过流向速度的概率密度函数检测了湍流区域中的等动量区. 使用了两种分类方法分析了等动量区在湍流边界层中的发展和演化, 对比研究了超疏水表面对等动量区特性的影响. 根据瞬时快照中包含的等动量区的数量对流场进行分类, 研究了湍流/非湍流界面的高度与流场中包含的等动量区数量之间的联系, 对比了不同类别流场的统计量, 讨论了等动量区在不同法向高度对于喷射/扫掠事件的贡献, 并讨论了结果在超疏水表面上的差异.The characteristics and dynamics of the uniform momentum zones(UMZs)on a smooth surface and a superhydrophobic(SHPo)surface in a turbulent boundary layer(TBL)are studied using two-dimensional time-resolved particle image velocimetry(PIV)at Re_(τ)=uτδ/υ=528(where uτis the wall friction velocity,δis the thickness of the boundary layer,andυis the kinematic viscosity of water).The turbulent/non-turbulent interface(TNTI)is detected by the local turbulent kinetic energy deficit to remove the region of non-turbulent flow.Then the UMZs are detected from the probability density functions(PDFs)of the instantaneous streamwise velocity in the turbulent region.The characteristics of the UMZs are studied using two classification methods to summarize its development and evolution in the TBL.The effects of the SHPo surface on the characteristics of the UMZs are investigated by comparison.The instantaneous flow fields are classified according to the number of the UMZs contained.The connection between the height of the TNTI and the number of zones contained in the flow fields is summarized.The influence of UMZs on turbulence dynamics is investigated.The behaviors of ejections/sweeps and their contributions to Reynolds stress are discussed categorically using quadrant analysis as well as conditional average.The corresponding differences on the SHPo surface are discussed.

关 键 词：湍流边界层 光滑表面 超疏水表面 概率密度函数 瞬时速度 亏损率 统计量 动量 

分 类 号：O35[理学—流体力学]