A framework for modeling flow over flexible submerged aquatic vegetation

水下水生植被（SAV）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促进了沉积物的稳定性，为许多重要物种提供了食物和住所，并改善了水质。因此，SAV在自然生境和生物群落之间形成了关键的联系。柔性SAV叶片与流场以及彼此之间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，SAV的冠层会发生连续运动（monami），这与SAV上附着的藻类的丰度有关。迄今为止，我们对SAV结构如何影响水流衰减和质量输运的理解仍然有限，植被叶片之间的物理相互作用在大多数观测工作、理论分析或模型研究中都没有明确地包括在内。该项目将开发一个由实地观测和实验支持的综合建模框架。新模型将支持工程师和自然资源管理人员，他们的任务是制定法律规定的弹簧恢复的最低流量要求。该项目支持两名博士生，他们将在水动力建模、水生生态学和数据分析方面接受跨学科培训。一个动手推广活动和K-12课程计划将在UF海岸实验室使用便携式赛道水槽开发。本研究的主要目标是量化植被结构特性和叶片间相互作用对水动力学的影响，并表征不同流动条件下柔性植被冠层的集体行为。本研究开发了一种将软体动力学集成到有限元模型中的结构求解器，用于研究植被叶片的变形和多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，以研究相互作用的淹没柔性植被的流动。将在佛罗里达多个泉进行实地观测，其中测速仪和摄像机将收集水动力学和植被冠层数据（如有效植被高度和单浪特征）。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流动条件的不同流型。本项目将利用观测数据和模型结果，在河段尺度上改进SAV对水动力影响的参数化方法，并将其应用于大规模模型框架中，以研究SAV对泥沙输运和藻类生长动态等关键生态系统过程的影响。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.