Refinement three-dimensional simulation of effect of floodplain vegetation on hydrodynamic characteristics in compound open channel based on Fluent software
YANG Yingyi, LI Dongzi, MA Yongshun, ZHANG Mingliang*
College of Marine Science and Environment, Dalian Ocean University, Dalian 116023, China
Abstract: In order to investigate the effect of the floodplain vegetation on the hydrodynamic characteristics in the compound open channel to understand of mechanism of hydrodynamic exchange in floodplain under vegetion, the fluid mechanics software (Fluent) was adopted to simulate the flow characteristics and to understand the flow momentum exchange between the floodplain and the main channel of the compound open channel in the presence of vegetation. The standard k-ε turbulence model was chosen to close N-S equations in the Fluent software, and the influences of the floodplain plant on the velocity, turbulent kinetic energy and the secondary flow in the section of the compound open channel were analyzed under the conditions of different submerged vegetation heights and different inflow rates. It was found that the vertical velocity of main stream in vegetation region presented no more logarithmic distribution, with quasi “S” type distribution. The results showed that the velocity of the main stream in the vegetated area was decreased compared with that in absence of vegetation, with the increase in the vegetation height, and decrease in the vegetated region, while the velocity in the main channel was increased correspondingly. Thus the plants blocked the flow movement in the floodplain, and made the mainstream transfer to the main channel of the river. The plants in the floodplain made a disturbance for the transverse velocity and enhanced the formation of the secondary flow. In the vegetation area, the vertical change in turbulent kinetic energy near the top of the vegetation was violent, and the turbulent kinetic energy at the interface of vegetation was also changed significantly with the increase in the vegetation height in the floodplain, indicating that there was a large kinetic energy exchange at the top of vegetation. In addition, the velocity of main stream was increased with the increase in the inflow discharge, and the vertical turbulent kinetic energy was increased correspondingly. The findings indicate that Fluent software can well simulate the impact of the floodplain vegetation on the hydrodynamic characteristics in compound river, and that provide scientific and reference basis for some projects including the implementation of river flood control, river shoal regulation and ecological bank protection.
杨颖宜, 李东子, 马永顺, 张明亮. 基于Fluent仿真软件的滩地植被作用下复式河道水动力特性的精细化数值模拟[J]. 大连海洋大学学报, 2021, 36(2): 317-324.
YANG Yingyi, LI Dongzi, MA Yongshun, ZHANG Mingliang. Refinement three-dimensional simulation of effect of floodplain vegetation on hydrodynamic characteristics in compound open channel based on Fluent software. Journal of Dalian Ocean University, 2021, 36(2): 317-324.
2021, Vol. 36 
