The Effect of Submerged and Emergent, Highly Flexible and Rigid Macrophyte Canopy Patches on Flow and Mass Transport

建议没有。当前位置主要研究者：EDWIN a . cowen研究机构：康奈尔大学水下和突发、高柔性和刚性大型植物冠层斑块对水流和物质运输的影响这项资助用于开展一系列精心控制的实验研究，研究水生大型植物冠层斑块对低速水流的影响。关于陆生和水生植被对水流影响的文献越来越多，但关于非均质冠层对低速水流影响的水生植物文献和一般高度灵活的大型植物对水流影响的文献还存在明显的空白。研究人员将收集一个规范的实验数据集，记录高度灵活的大型植物冠层和异质大型植物斑块对低速流动和物质运输的影响。第二个目标是扩展和研究现有湍流闭合方案捕捉这些效应的能力。实验将使用两种活的大型植物进行。大型植物将被放置在一个宽明渠水槽的全玻璃试验段中越来越复杂的斑块中。最先进的定量成像技术将用于测量湍流速度特性，包括直接计算的湍流耗散，以及荧光示踪剂的传输和色散。对湍流闭合模型提出的修改将是研究模型捕捉湍流动能收支能力的起点。在均匀的水生冠层中表现同样良好的冠层流动的竞争数值模型将针对这种新的异质数据集进行测试。收集到的数据集将填补我们对水生植物与水流相互作用理解的关键空白。与活的植物一起工作是很重要的，因为野外生物学家监测大型植物群落使用的指标不适合用模拟的植物模型结果进行缩放。经过测试的湍流闭合模型将允许开发能够预测由高度灵活和异质性植物冠层斑块主导的自然环境中的运输的计算工具，这些环境包括各种规模的湖泊、盐沼、河口和海岸码头以及陆地流。该项目将为一名有才华的女学生提供跨学科的博士学位，她将与PI一起为流体力学入门课程开发实验室经验，并为一个针对对科学和工程感兴趣的高中女生的项目主持为期一周的项目。

PROPOSAL NO.: CTS-0626164PRINCIPAL INVESTIGATOR: EDWIN A. COWENINSTITUTION: CORNELL UNIVERSITYTHE EFFECT OF SUBMERGED AND EMERGENT, HIGHLY FLEXIBLE AND RIGID MACROPHYTE CANOPY PATCHES ON FLOW AND MASS TRANSPORT This grant provides funding to perform a series of carefully controlled experimental studies on the effects of aquatic macrophyte canopy patches on low-speed flows. The literature on the effects of terrestrial and aquatic vegetation on flow is becoming quite rich but there is a significant gap in the aquatic plant literature on the effects of heterogeneous canopies in low-speed flows and for the effects of highly flexible macrophtyes in general. The investigators will collect a canonical experimental data set documenting the effects of highly flexible macrophyte canopies and heterogenous macrophyte patches on low-speed flow and mass transport. A secondary goal is to extend and investigate the ability of existing turbulence closure schemes to capture these effects. The experiments will be conducted using two species of live macrophytes. The macrophytes will be placed in patches of increasing complexity in the all glass test section of a wide open-channel flume. State of the art quantitative imaging techniques will be used to measure the turbulent velocity characteristics, including the directly calculated turbulent dissipation, as well as the transport and dispersion of fluorescent tracers. Proposed modifications to turbulence closure models will be the starting point for investigating the ability of models to capture the turbulent kinetic energy budget. Competing numerical models of canopy flow that perform equally well in uniform aquatic canopies will be tested against this novel heterogeneous data set. The collected data set will fill critical gaps in our understanding of aquatic plant-flow interaction. It is important to work with live plants, as field biologists monitor macrophyte communities using metrics that do not lend themselves to scaling with simulated plant model results. The tested turbulence closure models will allow the development of computational tools capable of forecasting transport in natural environments dominated by both highly flexible and heterogeneous plant canopy patches - environments such as lakes of all scales, salt marshes, estuaries and coastal embayments and terrestrial flows as well. The project will lead to an interdisciplinary Ph.D. for a talented female student who will work with the PI to develop laboratory experiences for an introductory fluid mechanics course and to host weeklong projects for a program targeting high-school women interested in science and engineering.