Effect of Mixed Vegetation of Different Heights on Open Channel Flows  

作　　者：Xiaonan Tang Yutong Guan Ming Li Hanyi Wang Jiaze Cao Suyang Zhang Nanyu Xiao Xiaonan Tang;Yutong Guan;Ming Li;Hanyi Wang;Jiaze Cao;Suyang Zhang;Nanyu Xiao(Department of Civil Engineering, Xi’an Jiaotong-Liverpool University, Suzhou, China;Department of Civil Engineering, The University of Liverpool, Liverpool, UK)

机构地区：[1]Department of Civil Engineering, Xi’an Jiaotong-Liverpool University, Suzhou, China [2]Department of Civil Engineering, The University of Liverpool, Liverpool, UK

出　　处：《Journal of Geoscience and Environment Protection》2023年第3期305-314,共10页地球科学和环境保护期刊（英文）

摘　　要：Vegetation of different heights commonly grows in natural rivers, canals and wetlands and affects the biodiversity and morphological process. The role of vegetation has drawn great attention in river ecosystems and environmental management. Due to the complexity of the vegetated flow, most previous research focuses on the effect of uniformed one-layered vegetation on the flow structure and morphological process. However, less attention was paid to the impact of the mixing vegetation of different heights, which is more realistic and often occurs in natural riverine environments. This paper aims to investigate the effect of mixing three-layered vegetation on flow characteristics, particularly the velocity distrbution, via a novel experiment. Experiments were performed in a titling water flume fully covered with vegetation of three heights (10, 15 and 20 cm) arranged in a staggered pattern, which is partially submerged. Velocities at different positions along a half cross-section were measured using a mini propeller velocimeter. Observed results showed that the velocity has a distinct profile directly behind vegetation and behind the vegetation gap. The overall profile has two distinct reflections about ? below or near the top of short vegetation (h): the velocity remains almost constant in the bottom layer ( h) the velocities directly behind the middle after short vegetation increase much faster than those directly behind the short after tall vegetation. The finding in this study would help river riparian and ecosystem management. .Vegetation of different heights commonly grows in natural rivers, canals and wetlands and affects the biodiversity and morphological process. The role of vegetation has drawn great attention in river ecosystems and environmental management. Due to the complexity of the vegetated flow, most previous research focuses on the effect of uniformed one-layered vegetation on the flow structure and morphological process. However, less attention was paid to the impact of the mixing vegetation of different heights, which is more realistic and often occurs in natural riverine environments. This paper aims to investigate the effect of mixing three-layered vegetation on flow characteristics, particularly the velocity distrbution, via a novel experiment. Experiments were performed in a titling water flume fully covered with vegetation of three heights (10, 15 and 20 cm) arranged in a staggered pattern, which is partially submerged. Velocities at different positions along a half cross-section were measured using a mini propeller velocimeter. Observed results showed that the velocity has a distinct profile directly behind vegetation and behind the vegetation gap. The overall profile has two distinct reflections about ? below or near the top of short vegetation (h): the velocity remains almost constant in the bottom layer ( h) the velocities directly behind the middle after short vegetation increase much faster than those directly behind the short after tall vegetation. The finding in this study would help river riparian and ecosystem management. .

关 键 词：Rigid Vegetation Mixed-Layered Vegetation RIPARIAN Velocity Distribution Submerged Flow Open Channel 

分 类 号：Q94[生物学—植物学]