Numerical and analytical flow models in ecological channels with interaction of vegetation and freshwater

Frontiers in Environmental Science

Environmental Science

Zhiwu Liu¹  Hanqing Zhao²  Fengcong Jia³  Huilin Wang⁴  Weijie Wang⁵  Yuxuan Xu⁶ 

[1] China Three Gorges Corporation, Wuhan, China;China Three Gorges Corporation, Wuhan, China;National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety, Nanjing, China;College of Water Resources and Civil Engineering, China Agricultural University, Beijing, China;School of Water Conservancy and Civil Engineering, South China Agricultural University, Guangzhou, China;State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing, China;State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing, China;School of Water Conservancy, North China University of Water Resources and Electric Power, Zhengzhou, China;

关键词: numerical model;    analytical model;    vegetated flow;    velocity profile;    Manning’s coefficient;   

DOI  :  10.3389/fenvs.2023.1098993

 received in 2023-01-06, accepted in 2023-04-18,  发布年份 2023

来源: Frontiers

【 摘 要 】

Aquatic vegetation interferes with river hydrodynamics, thus affecting the mass transport and energy transfer in an ecosystem. The flow over submerged vegetation is characterized by a complex velocity profile and multiple turbulence structures, which have been usually simulated using cylinders or strips in previous studies. Because the simplified vegetation configuration may hide or amplify some physical processes found in natural conditions, we investigate the velocity distribution and turbulence structure in foliaged vegetation flows using both analytical and numerical approaches. The main innovations and findings can be summarized as follows: 1) numerical and analytical models adopted in this paper accurately simulate the flow velocity profile in vegetated channel; 2) the Karman constant is found to be unsuitable for complex vegetation morphologies, so we proposed adjusted coefficient; 3) an image processing method is adopted to quantify the vegetation morphology accurately; 4) the existing mixing-layer thickness formula is found to be unsuitable for vegetation with leaves, an improved formula is proposed showing high correlation coefficient (0.9562) between measured and predicted data; 5) to ensure applicability to larger-scale hydrodynamic simulations, an analytical expression of Manning’s coefficient is proposed based on an analytical multi-layer flow velocity model. These research findings can provide theoretical support for the design of vegetated river and ecological restoration.

【 授权许可】

Unknown   
Copyright © 2023 Zhao, Wang, Jia, Wang, Liu and Xu.