A framework for modeling flow over flexible submerged aquatic vegetation

沉水植被在河流和河口过程中起着重要的作用。通过衰减水流和调节水流湍流，SAV促进沉积物稳定，为许多重要物种提供食物和庇护所，并改善水质。因此，SAV形成了物理栖息地和生物群落之间的重要联系。灵活的SAV叶片与流场相互作用，并以复杂但具有生态意义的方式相互作用。例如，在临界流速阈值以上，发生连续的SAV冠层运动（单波），这与SAV上附着的藻类的丰度相关。迄今为止，我们的理解如何SAV结构影响流量衰减和质量传输仍然是有限的，和植被叶片之间的物理相互作用没有明确包括在大多数观测工作，理论分析或建模研究。该项目将开发一个由实地观察和实验支持的综合建模框架。新模型将为工程师和自然资源管理人员提供支持，他们的任务是为泉水恢复制定法律规定的最低流量要求。该项目支持两名博士生，他们将接受流体动力学建模，水生生态学和数据分析的跨学科培训。一个动手推广活动和K-12课程计划将开发使用便携式跑道水槽在UF海岸实验室。本研究的主要目标是量化的植被结构特性和叶片对叶片的相互作用对流体力学的影响，并在不同的流动条件下的灵活的植被冠层的集体行为的特征。该研究开发了一种结构求解器，将软体动力学集成到有限元模型中，以研究植被叶片的变形和多个叶片之间的相互作用。结构模型将与计算流体动力学模型相结合，以研究相互作用的水下柔性植被上的水流。将在多个佛罗里达泉进行实地观测，其中速度计和摄像机将收集水动力学和植被冠层数据（如有效植被高度和藻波特征）。该模型将与观测数据进行验证，然后用于识别基于植被结构特性和水流条件的不同水流状态。本项目将利用观测数据和模型结果，改进SAV对河流河段水动力学影响的参数化，可在大尺度模型框架中实施，以研究SAV对关键生态系统过程的影响，该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准。

Submerged aquatic vegetation (SAV) plays an important role in riverine and estuarine processes. By attenuating flow and modulating flow turbulence, SAV promotes sediment stability, provides food and shelter for numerous important species and improves water quality. SAV thus forms a critical link between physical habitat and biological communities. Flexible SAV blades interact with the flow field and with each other in complex, but ecologically significant ways. For example, above a critical flow velocity threshold, continuous SAV canopy motion (monami) occurs, which is associated with the abundance of attached algae on SAV. To date, our understanding of how SAV structure affects flow attenuation and mass transport is still limited, and physical interactions among vegetation blades are not included explicitly in most observational efforts, theoretical analyses or modeling studies. This project will develop an integrated modeling framework supported by field observations and experiments. The new model will support engineers and natural resources managers tasked with developing legally mandated minimum flow requirements for springs restoration. The project supports two PhD students, who will receive interdisciplinary training in hydrodynamic modeling, aquatic ecology, and data analysis. A hands-on outreach activity and K-12 lesson plan will be developed using a portable racetrack flume at the UF Coastal Lab.The primary goal of this study is to quantify the influence of vegetation structural properties and blade-to-blade interactions on hydrodynamics and characterize the collective behavior of flexible vegetation canopies under different flow conditions. The study develops a structural solver that integrates soft-body dynamics into a finite element model to investigate the deformation of vegetation blades and interactions between multiple blades. The structural model will be coupled with a computational fluid dynamics model to study flow over interacting submerged flexible vegetation. Field observations in multiple Florida springs will be carried out, in which velocimeters and video cameras will collect hydrodynamics and vegetation canopy data (such as effective vegetation heights and monami characteristics). The model will be validated with observational data, and then used to identify different flow regimes based on vegetation structural properties and flow conditions. This project will develop an improved parameterization of the effects of SAV on hydrodynamics on river reach-scale using observation data and model results, which can be implemented in large-scale modeling framework to study the effects of SAV on key ecosystem processes, such as sediment transport and algae growth dynamics.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.