ABSTRACT

Transverse solute mixing across a vegetation generated horizontal shear layer was quantified using laser induced fluorometry techniques for artificial and real vegetation. A two-dimensional finite difference model (FDM) was developed to describe transverse concentration profiles for flows containing transverse variations in velocity and transverse dispersion, from a steady solute input. The FDM was employed inversely, to optimize the parameters describing the transverse distribution of the transverse dispersion coefficient for vegetation generated shear layers. When laboratory data are available, continuous function descriptions produce slightly improved FDM modelled solute concentration profiles compared with simplified step discontinuity velocity and dispersion inputs. When laboratory data are not available, estimates of step or continuous transverse distributions from other work enable concentration profiles to be predicted with a similar goodness of fit. This paper presents a validated, simple, robust finite difference model to describe the mixing of solutes in a channel containing marginal vegetation.

摘要

使用激光诱导荧光分析技术对人工和真实植被进行定量，确定横跨植被产生的水平剪切层的横向溶质混合情况。建立了二维有限差分模型（FDM），以描述包含来自稳定溶质输入的速度和横向分散的横向变化的流的横向浓度分布。反向采用FDM，以优化描述植被产生的剪切层的横向色散系数的横向分布的参数。当可获得实验室数据时，与简化的阶跃不连续速度和分散度输入相比，连续功能描述会产生稍微改善的FDM模型溶质浓度曲线。如果没有实验室数据，其他工作的阶跃或连续横向分布的估计值可以以相似的拟合优度来预测浓度曲线。本文提出了一个经过验证的，简单的，鲁棒的有限差分模型，用于描述溶质在包含边缘植被的河道中的混合。