The effect of unsteady turbulent flows on mass transfer in aquatic environments

非定常湍流对水生环境中传质的影响

• 批准号: RGPIN-2015-05680
• 负责人: Ackerman, Josef
• 金额: $ 1.97万
• 依托单位: University of Guelph
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=643422
• 关键词: effect; unsteady; turbulent; flows; mass

The objectives of the proposed research program are to examine the role of mass transport on fundamental biogeochemical and ecological processes using a combination of experimental, field, and computational approaches. Specifically, I will examine the influence of turbulence on nutrient uptake, suspension feeding/particle fate, and particle flux that occur in the benthos (sediments, macrophytes, bivalves) of aquatic systems. In doing so, I will examine the role of unsteady flow - including the fluid-structure interactions that cause organisms to oscillate - in addition to the influence of mean flow conditions on these processes. My specific objectives are to investigate/determine the: (1) fluid-macrophyte interactions and how turbulence-induced plant movements affect macrophyte productivity through the transport and uptake of dissolved inorganic carbon to the leaf surface where nutrient uptake occurs; (2) fate of particles (including biological ones) transported through beds of suspension feeding freshwater mussels; and (3) the effect of collector motion on particle capture, which is an essential mass transport mechanism. The fulfillment of these objectives relates directly to a better understanding of the productivity and function of aquatic environments.***As an empiricist, I operate within a theoretical framework set by the fluid dynamics and modified by the specific attributes of the organism/system under study. This allows me to establish hypotheses based on existing physical theory and to examine whether ecological/biogeochemical processes conform to the expectations of that theory. In this way, it is possible to draw broader conclusions and further the development of theories of organism-environmental interactions. This often requires the use of a simplification, such as restricting the movement/geometry of an organism and using steady flow conditions, to ensure that conditions conform to the physical model (e.g. leaves of a plant must be flat and parallel to the flow direction to examine mass transport using the flat plate analogy). By incorporating unsteady flow conditions, including flow-induced interactions, I will be able to advance our understanding of biogeochemical/ecological response to hydrodynamics forcing. The results of this research program will facilitate the development of novel models of the unsteady conditions found in nature, which will inform scientists, engineers, and managers. There are direct implications for the fate/transport of contaminants, which are influenced if not dominated by surface phenomena. The results will also be used to address/mitigate the impacts of human activities on habitat and on water quality.**

拟议研究计划的目标是结合实验、现场和计算方法来研究质量传递对基本生物地球化学和生态过程的作用。具体来说，我将研究湍流对水生系统底栖生物（沉积物、大型植物、双壳类动物）中养分吸收、悬浮摄食/颗粒命运以及颗粒通量的影响。在此过程中，除了平均流量条件对这些过程的影响之外，我还将研究非定常流动的作用 - 包括导致生物体振荡的流体-结构相互作用。我的具体目标是研究/确定：（1）流体与大型植物的相互作用，以及湍流引起的植物运动如何通过将溶解的无机碳运输和吸收到发生养分吸收的叶面来影响大型植物的生产力； (2) 通过悬浮饲养淡水贻贝的床输送的颗粒（包括生物颗粒）的命运； (3)收集器运动对粒子捕获的影响，这是一种重要的传质机制。这些目标的实现直接关系到更好地理解水生环境的生产力和功能。***作为一名经验主义者，我在由流体动力学设定并根据所研究的有机体/系统的特定属性进行修改的理论框架内进行操作。这使我能够根据现有的物理理论建立假设，并检验生态/生物地球化学过程是否符合该理论的预期。这样，就有可能得出更广泛的结论并进一步发展有机体与环境相互作用的理论。这通常需要进行简化，例如限制生物体的运动/几何形状并使用稳定流动条件，以确保条件符合物理模型（例如，植物的叶子必须平坦且与流动方向平行，才能使用平板类比检查质量传递）。 通过结合非定常流动条件，包括流动引起的相互作用，我将能够增进我们对生物地球化学/生态对流体动力学强迫的响应的理解。该研究计划的结果将有助于开发自然界中发现的不稳定条件的新颖模型，这将为科学家、工程师和管理者提供信息。这对污染物的命运/迁移有直接影响，即使不是受表面现象支配，也会受到影响。研究结果还将用于解决/减轻人类活动对栖息地和水质的影响。**