水科学进展2023，Vol.34Issue(6)：913-927,15.DOI:10.14042/j.cnki.32.1309.2023.06.009
沉水植被斑块尾流多尺度紊流结构研究
Investigation of wake flow on submerged vegetation patches based on spectral proper orthogonal decomposition
摘要
Abstract
The multi-scale turbulent structures enable understanding the vegetation patch-affected sediment transport and riverbed evolution.Here,flume-based wake flow characteristics were analysed under different aspect ratios and vegetation densities.The mean flow velocity and Reynolds stress distribution were obtained.The fluctuation field was analysed using the spectral proper orthogonal decomposition to obtain different scale eddies′spatial modes and energy distribution.We demonstrate the following:① The shear strength and non-dimensional shear layer thickness increased with the vegetation density and decreased with increasing canopy shear layer aspect ratio.②The wake flow large-scale eddies exhibited a 0.15-0.29 Hz frequency and 0.16-0.32 Strouhal number(Sr).The eddies exhibited 0.2-1.3 times higher vertical distribution than the vegetation and 2-6 times wider longitudinal distribution than the patch diameter.The eddies exhibited transverse distribution from the vegetation centreline.③ The wake region longitudinal outflow velocity and turbulence intensity affected the stable wake region length.The longitudinal outflow velocity and turbulence intensity determined the shear layer longitudinal transportation and vertical diffusion velocities,respectively.关键词
植被斑块/多尺度紊流/沉水植被/谱本征正交分解/尾流区长度Key words
vegetation patch/multi-scale turbulent structures/submerged vegetation/SPOD/the length of the wake region分类
建筑与水利引用本文复制引用
张维乐,吴时强,吴修锋,薛万云,王芳芳,张宇,於思瀚..沉水植被斑块尾流多尺度紊流结构研究[J].水科学进展,2023,34(6):913-927,15.基金项目
国家自然科学基金资助项目(52209032) （52209032）
江苏省自然科学基金资助项目(BK20221190)The study is financially supported by the National Natural Science Foundation of China(No.52209032)and the Natural Science Foundation of Jiangsu Province,China(No.BK20221190). （BK20221190）
