The Impact of Blade Motion on the Flux to a Blade Surface

叶片运动对叶片表面通量的影响

• 批准号: 1140970
• 负责人: Heidi Nepf
• 金额: $ 37.32万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-03-15 至 2017-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1140970&HistoricalAwards=false
• 关键词: Impact; Blade; Motion; Flux; Surface

Aquatic vegetation in fresh- and salt-water systems provides ecosystem services valued at over one trillion dollars per year. Seagrass and freshwater macrophytes enhance water quality by filtering nutrients from the water, reducing re-suspension, and producing oxygen in stagnant regions. Unlike terrestrial plants, which acquire nutrients through their roots, aquatic plants acquire essential nutrients through their leaves and blades from the surrounding water. The nutrient uptake controls the growth and health of the vegetation, as well as its potential impact on water quality. The proposed research will examine how the hydrodynamic conditions and the motion of individual blades impacts the rate of nutrient flux to the plant, with the goal of providing better predictions of the potential maximum uptake rate. The project will examine the interaction of individual blades with uni-directional current and progressive waves to understand how blade motion influences flux to the blade surface. The model blades will be constructed from low-density polyethylene (LDPE), which preferentially absorb the organic compounds present in our flume water (e.g. chloroform). Because of its high partitioning coefficient, for an initial period of exposure, the LDPE blade takes in chemicals as fast as it can be delivered to the surface, mimicking mass-transport limiting uptake. This project will extend existing models for flux at solid boundaries to conditions relevant to macrophytes, specifically introducing the impact of blade motion and conditions with waves. It will contribute a basic understanding of mass exchange at flexible boundaries that is relevant to chemical and biological engineering.

淡水和咸水系统中的水生植被每年提供价值超过1万亿美元的生态系统服务。 海草和淡水水生植物通过过滤水中的营养物质，减少再悬浮，并在停滞区域产生氧气来提高水质。 与陆生植物通过根部获取营养不同，水生植物通过叶片从周围的水中获取必需的营养。 养分吸收控制着植被的生长和健康，以及对水质的潜在影响。 拟议的研究将研究水动力条件和单个叶片的运动如何影响植物的养分通量速率，目的是更好地预测潜在的最大吸收速率。 该项目将研究单个叶片与单向水流和前进波的相互作用，以了解叶片运动如何影响叶片表面的通量。 模型叶片将由低密度聚乙烯（LDPE）制成，它优先吸收水槽水中的有机化合物（如氯仿）。 由于其高分配系数，在暴露的初始阶段，LDPE叶片以尽可能快的速度将化学品输送到表面，模仿质量传输限制吸收。该项目将扩展现有的固体边界通量模型到与水生植物相关的条件，特别是引入叶片运动和波浪条件的影响。 它将有助于在灵活的边界，是相关的化学和生物工程质量交换的基本理解。