Modelling Pollution Transport in Vegetated Flow Environment

植被通常存在于环境流域（如溪流、河流、湿地和河口）中，通过提供氧气和降低悬浮泥沙浓度在维持水质方面发挥重要作用。植被的存在下，由于植物茎尾流和由此产生的复杂的流体动力学结构的影响，提高了溶质的混合和扩散的植被。因此，模拟植被存在下的水流和污染物输运对于理解溶质在冠层内的混合和扩散以及环境水流是至关重要的，植被环境水流系统对淡水生态学和生物多样性具有重要意义。土壤、沉积物床、植被和生物在环境流动系统中的组合可以促进水的处理和溶质和固体污染的去除。正是水-植被-土壤之间的相互作用支配着影响污染物迁移和归宿的物理、化学和生物过程。水运动的动力学以及与植被的相互作用在确定环境流系统中污染物的混合和扩散方面起着关键作用。植物群落对这些流动系统的流体动力学和性能具有显著影响，因为它们产生流动阻力，改变速度场，并影响混合特性，使悬浮物质落到流动域的床。植被生长和枯死的季节变化影响这些系统的性能。然而，关键的知识差距仍然存在的污染物的来源和归宿在植被环境流systems.The主要目的是确定和量化的关键机制，利用实验室研究和基于现场的数据收集的污染物的运输和归宿我们的行业合作伙伴，诺福克河流信托。该项目还将使用物理和现场数据来开发和验证数值模型，以模拟溶质和微塑料与植被流和沉积床的相互作用。该项目提供的新见解将有助于了解植被淡水流系统中污染物传输的动态。因此，该项目将通过了解和量化污染物在植被流中的迁移和归宿，在环境保护和综合集水区管理方面实现一个步骤性变化，并在淡水系统面临相当大的污染压力时产生重大影响。我们将利用沃里克水实验室的世界级实验设施，创造一个相互作用的中生态系统河流和湿地环境。将应用荧光示踪沿着新的颗粒染色技术，与平面激光诱导荧光（PLIF）一起，旨在识别和量化污染物的基本物理传输机制以及水力条件对污染物传输和归宿的影响。将通过基于雷诺平均纳维尔-斯托克斯（RANS）和大涡模拟（LES）方法开发数值模型，模拟（河流和湿地中的）污染物和污染物特性。我们将建立刚性和柔性植被标量输运的粒子模型。将根据实验数据对数值模型进行验证，并将进行情景建模。

Vegetation is often present in environmental flow domains (e.g. streams, rivers, wetlands, and estuaries), playing an important role in maintaining the water quality by providing oxygen and reducing the suspended sediment concentration. The presence of vegetation enhances solute mixing and diffusion within the vegetation due to the effects of the plant stem wake and the resulting complex hydrodynamic structure. Hence, modeling the flow and pollutant transport in the presence of vegetation is vital for understanding solute mixing and the diffusion within a canopy, and environmental flows.Vegetated environmental flow systems are significantly important for freshwater ecology and biodiversity. The combination of soil, sediment bed, vegetation, and organisms in environmental flow systems can facilitate treatment of water and removal of solute and solid pollution. It is the interplay between water-vegetation-soil that governs the physical, chemical and biological processes influencing pollution transport and fate. Dynamics of water movement and the interactions with vegetation plays a key role in determining the mixing and dispersion of pollutants in environmental flow systems. Plant communities have a prominent effect on the hydrodynamics and performance of these flow systems, as they generate flow resistance, changes the velocity field, and affect mixing characteristics, enabling suspended material to fall to the bed of the flow domain. Seasonal variation in vegetation growth and die-back influences the performance of these systems. However, critical knowledge gaps remain in sources and fate of pollutants in vegetated environmental flow systems.The main aim is to identify and quantify key mechanisms that govern the transport and fate of pollutants using laboratory studies and field-based data collected by our industry partner, Norfolk Rivers Trust. This project will also use the physical and field-based data to develop and validate numerical model to simulate the interaction of solute and microplastics with vegetated flows and sediment bed. The new insights offered by this project will enable understanding the dynamics of pollutant transport in vegetated freshwater flow systems. Hence this project will provide a step change in environmental protection and integrated catchment management by understanding andquantifying the pollution transport and fate in vegetated flows, and significantly, be influential at a time of considerable pollution stress on freshwater systems.This project will undertake laboratory-based physical modelling measurements and fieldwork data collection to understand the dynamics of pollutant transport in rivers and wetlands. We will create an interacting mesocosm river and wetland environments using the world class experimental facility at Warwick Water Laboratory. Fluorometric tracing along with novel particle staining techniques will be applied, alongside planar laser-induces fluorescence (PLIF) with the aim of identifying and quantifying underlying physical transport mechanisms of pollutants and the impact of hydraulic conditions on the transport and fate of the pollutant.The effects of vegetation on the flow (in rivers and wetlands) and pollutant characteristics will be modelled by developing numerical models based on the Reynolds averaged Navier-Stokes (RANS) and large eddy simulation (LES) method. We will develop particle model of scalar transport for both rigid and flexible vegetation. The numerical model will be validated against experimental data and scenario modelling will be performed.