工程科学与技术2024，Vol.56Issue(3)：197-207,11.DOI:10.12454/j.jsuese.202200872
基于涡识别技术的微结构壁面湍流减阻机理研究
Research on Turbulent Drag Reduction Mechanism of Microstructure Walls Using Vortex Recognition Technology
摘要
Abstract
To investigate the turbulent drag reduction characteristics of microstructure walls,the particle image velocimetry system was utilized to observe water flow characteristics across superhydrophobic,riblet,and smooth walls.The study delved into the evolution of flow velocity,vari-ations in Reynolds shear stress,and vortex distribution.Enhancements were made to the Omega(Ω)vortex identification method,incorporating flow rate to establish a novel ΩM vortex identification method.Inspired by meteorological concepts of atmospheric vortex density,a correspond-ing definition for vortex density in liquid flow was proposed to quantify the distribution of vortices of differing strengths.Results demonstrated that,at equivalent Reynolds numbers,flow velocity decreased sequentially from superhydrophobic to riblet to smooth walls.Notably,the flow ve-locity of microstructure walls exhibited pronounced outward shifts compared to that of smooth walls,indicating drag reduction effects.Concur-rently,Reynolds shear stress initially increased then decreased with increasing normal dimensionless distance(y+),with the superhydrophobic wall exhibiting the smallest maximum Reynolds shear stress among all walls.In the vortex structures identified using the ΩM method,weak vor-tices on microstructure walls decreased significantly within a water depth range of 0.1 times,while strong vortices weakened within a range of 0.2 times the water depth.Notably,the vortex density of weak vortices increased on microstructure walls compared to smooth walls,whereas the density of strong vortices decreased,suggesting that microstructure walls inhibited the development of strong vortices.The drag reduction ratio of riblet walls exceeded 7.60%,while superhydrophobic walls exhibited a higher density of weak vortices and a lower density of strong vortices,res-ulting in the most significant drag reduction effect surpassing 9.48%.Microstructure walls thus prove effective in reducing energy consumption in water transport and enhancing transport efficiency.关键词
超疏水壁面/沟槽壁面/ΩM方法/涡密度/减阻Key words
super hydrophobic wall/riblet wall/ΩM method/vortex density/drag reduction分类
建筑与水利引用本文复制引用
刘春烨,王文娥,周士越,胡明宇,凌刚,胡笑涛..基于涡识别技术的微结构壁面湍流减阻机理研究[J].工程科学与技术,2024,56(3):197-207,11.基金项目
国家自然科学基金(52079113) （52079113）
国家自然科学基金重点项目(U2243235) （U2243235）
