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

使用人造和真实植被的激光诱导荧光测定技术对植被产生的水平剪切层中的横向溶质混合进行量化。开发了二维有限差分模型 (FDM) 来描述来自稳定溶质输入的包含速度和横向扩散的横向变化的流动的横向浓度分布。FDM 被反向使用，以优化描述植被产生的剪切层横向分散系数的横向分布的参数。当实验室数据可用时，与简化的阶跃不连续速度和分散输入相比，连续函数描述会产生略微改进的 FDM 建模溶质浓度曲线。当实验室数据不可用时，来自其他工作的阶跃或连续横向分布的估计使浓度分布能够以类似的拟合优度进行预测。本文提出了一个经过验证的、简单的、稳健的有限差分模型来描述包含边缘植被的通道中溶质的混合。