Zhang Jingzhou, Zhang Shengtang, Wang Chuantao, Wang Wenjun, Ma Lijun
College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao, China.
Front Plant Sci. 2022 Oct 11;13:976646. doi: 10.3389/fpls.2022.976646. eCollection 2022.
To clarify the flow characteristics of open channels under the combined distribution of vegetation in a patch, this study used the computational fluid dynamics tool FLUENT and the Reynolds stress model to design four combined and four discrete distribution modes under two different inundation states (submerged and non-submerged). The flow characteristics of longitudinally discontinuous rigid vegetation patches occupying half the width of the channel were numerically simulated. The numerical model is verified by indoor open channel flume experiments, and the obtained model data is in good agreement with the measured data. The results showed that: 1) The diameter of vegetation is an important factor affecting the wake structure. Under the submerged condition. 2)The submerged state, distribution pattern and combination form of vegetation are important factors that affect the distribution of flow velocity and change the structure of water flow. That is, the influence of vegetation distribution pattern on flow velocity and turbulence intensity under submerged condition is significantly weaker than that under non-submerged condition, and the flow velocity in non-vegetation area is significantly higher than that in vegetation area. The increase in the combined vegetation comprehensive stem thickness and the discrete degree resulted in an increase in the difference in flow velocity and turbulence intensity. 3) As the water flowed downstream, the flow velocity along the vegetated area continuously decreased, while it increased continuously along the non-vegetated area, and the difference in flow velocity between the two areas became more apparent. 4) The inundation state and combination characteristics of vegetation were important factors affecting the Reynolds stress of the channel location in the patch area.
为了阐明斑块状植被组合分布下明渠的水流特性，本研究使用计算流体动力学工具FLUENT和雷诺应力模型，在两种不同淹没状态（淹没和非淹没）下设计了四种组合分布模式和四种离散分布模式。对占据渠道一半宽度的纵向不连续刚性植被斑块的水流特性进行了数值模拟。通过室内明渠水槽实验对数值模型进行了验证，所得到的模型数据与实测数据吻合良好。结果表明：1）植被直径是影响尾流结构的重要因素。在淹没条件下。2）植被的淹没状态、分布模式和组合形式是影响流速分布和改变水流结构的重要因素。即，淹没条件下植被分布模式对流速和湍流强度的影响明显弱于非淹没条件，非植被区域的流速明显高于植被区域。组合植被综合茎厚度和离散度的增加导致流速和湍流强度差异增大。3）随着水流向下游流动，植被区域的流速持续降低，而非植被区域的流速持续增加，两个区域之间的流速差异变得更加明显。4）植被的淹没状态和组合特性是影响斑块区域渠道位置雷诺应力的重要因素。
