CURVED OPEN CHANNEL FLOW ON VEGETATION ROUGHENED INNER BANK

• Published in: Journal of hydrodynamics. Series B Vol. 24; no. 1; pp. 124 - 129
• Main Authors: HUAI, Wen-xin, LI, Cheng-guang, ZENG, Yu-hong, QIAN, Zhong-dong, YANG, Zhong-hua
• Format: Journal Article
• Language: English
• Published: Singapore Elsevier Ltd 01.02.2012; Springer Singapore; State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China
• Subjects: Banks; bend flow; Channels; Circulation; Curved; Engineering; Engineering Fluid Dynamics; Freshwater; Hydrology/Water Resources; Mathematical models; non-submerged rigid vegetation; Numerical and Computational Physics; Numerical prediction; River banks; RNG k – ɛ numerical model; shear stress; Simulation; stream-wise velocities; Vegetation; 内部银行; 实验室测量; 数值模型; 数值预报; 明渠流量; 植被覆盖; 流场结构; 粗糙; non-submerged rigid vegetation; RNG k – ɛ numerical model; stream-wise velocities; shear stress; bend flow; ε numerical model; RNG; RNG k-ε numerical model
• DOI: 10.1016/S1001-6058(11)60226-6
• ISSN: 1001-6058

A RNG numerical model together with a laboratory measurement with Micro ADV are adopted to investigate the flow through a 180o curved open channel（a 4 m straight inflow section,a 180o curved section,and a 4m straight outflow section）partially covered with rigid vegetations on its inner bank.Under the combined action of the vegetation and the bend flow,the flow structure is complex.The stream-wise velocities in the vegetation region are much smaller than those in the non-vegetation region due to the retardation caused by the vegetation.For the same reason,no clear circulation is found in the vegetated region,while in the non-vegetation region,a slight counter-rotating circulation is found near the outer bank at both 90o and downstream curved cross-sections.A comparison between the numerical prediction and the laboratory measurement shows that the RNG model can well predict the flow structure of the bend flow with vegetation.Furthermore,the shear stress is analyzed based on the numerical prediction.The much smaller value in the inner vegetated region indicates that the vegetation can effectively protect the river bank from scouring and erosion,in other words,the sediment is more likely to be deposited in the vegetation region.