Wang Shiyu, Zhou Yi, Li Tongshu, Li Song, Zhang Mingwu, Han Yu
College of Water Resources and Civil Engineering, China Agricultural University, Beijing, China.
Yellow River Institute of Hydraulic Research, Yellow River Conservancy Commission, Zhengzhou, China.
Front Plant Sci. 2021 Nov 22;12:753613. doi: 10.3389/fpls.2021.753613. eCollection 2021.
Ecological management of river channels is a hot topic for current sustainable development and flow measurement of ecological river is an important part. In this article, a flow velocity distribution model of the channel containing flexible vegetation is constructed from the vegetation riverbed theory and the bursting phenomenon to reveal the microscopic mechanism of the flow velocity distribution in the upper layer of vegetation. In the vegetation riverbed law, the effect of flexible vegetation is evaluated by the mixed length formula. The bursting phenomenon law considers the influence of the channel sidewalls on the flow and a two-dimensional velocity model is established by introducing the concept of average turbulence structure. The mechanism of the downward shift of the maximum flow velocity point on the channel sidewall is explained. The verification of the calculated velocity profiles is carried out based on data obtained in laboratory experiments. The results show that the combination of the two models can well describe the velocity distribution of the whole channel. At the end, the phenomenon of flow velocity zoning in open channel is discussed, which provides a solution for flow measurement in ecological channel.
河道生态管理是当前可持续发展的热门话题，生态河道流量测量是其重要组成部分。本文从植被河床理论和猝发现象出发，构建了含柔性植被河道的流速分布模型，以揭示植被上层流速分布的微观机制。在植被河床定律中，通过混合长度公式评估柔性植被的作用。猝发现象定律考虑了河道侧壁对水流的影响，并通过引入平均湍流结构的概念建立了二维流速模型。解释了河道侧壁上最大流速点下移的机制。基于实验室实验获得的数据对计算得到的流速剖面进行了验证。结果表明，两种模型的结合能够很好地描述整个河道的流速分布。最后，讨论了明渠流速分区现象，为生态河道流量测量提供了解决方案。
