Vertical dispersion in vegetated shear flows
Vertical dispersion in vegetated shear flows
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DOI：
10.1002/2016wr018907
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发表时间：
2016-10
影响因子：
5.4
通讯作者：
S. Rubol;I. Battiato;F. D. de Barros
中科院分区：
文献类型：
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作者：
S. Rubol;I. Battiato;F. D. de Barros
冠层控制着动量和溶质从上覆水表面层向上覆水表面层的输送。这些传输机制强烈依赖于冠层的几何形状，影响河流中的溶质的量，水文保留和溶解的溶质位于植被层中的生物体的可用性，是至关重要的，以改善水质。在这项工作中，我们考虑在充分发展的流动条件下，在一个植被通道的稳态运输。在假设冠层可以被描述为具有规定性质的有效多孔介质的情况下，即，孔隙率和渗透率，我们用一个具有空间可变弥散系数（扩散率）的平流弥散方程来模拟植被层上方和内部的溶质运移。本文利用广义积分变换技术，导出了沉水植物水生系统中浓度场的半解析解。我们发现，冠层的渗透性影响浓度分布的不对称性，有效的垂直传播行为，和峰值浓度的大小。由于其分析功能，该模型具有较低的计算成本。所提出的解决方案成功地再现了以前发表的实验数据。
Canopy layers control momentum and solute transport to and from the overlying water surface layer. These transfer mechanisms strongly dependent on canopy geometry, affect the amount of solute in the river, the hydrological retention and availability of dissolved solutes to organisms located in the vegetated layers, and are critical to improve water quality. In this work, we consider steady state transport in a vegetated channel under fully developed flow conditions. Under the hypothesis that the canopy layer can be described as an effective porous medium with prescribed properties, i.e., porosity and permeability, we model solute transport above and within the vegetated layer with an advection‐dispersion equation with a spatially variable dispersion coefficient (diffusivity). By means of the Generalized Integral Transform Technique, we derive a semianalytical solution for the concentration field in submerged vegetated aquatic systems. We show that canopy layer's permeability affects the asymmetry of the concentration profile, the effective vertical spreading behavior, and the magnitude of the peak concentration. Due to its analytical features, the model has a low computational cost. The proposed solution successfully reproduces previously published experimental data.