Collaborative Research: Improved observation and parameterization of bottom boundary layer turbulence and particle properties for sediment fate and transport modeling

合作研究：改进底部边界层湍流和颗粒特性的观测和参数化，以进行沉积物归宿和输运建模

• 批准号: 1736668
• 负责人: Oliver Fringer
• 金额: $ 137.59万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-15 至 2022-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1736668&HistoricalAwards=false
• 关键词: Collaborative; Research; Improved; observation; parameterization

Sediment fate and transport models are often utilized to help address environmental questions related to the environmental impacts of remediation efforts, the potential for reliable natural recovery, and the potential impacts of extreme events. In order to effectively implement sediment fate and transport models, bed erosion and deposition rates must be accurately parameterized. These processes are dependent on physical forcing, the distribution of sediment in the water column, and the properties of sediment such as bulk density, particle size, and biogeochemical composition. This research will employ high-resolution numerical simulations along with analysis of in-situ measurements of physical processes and particle characteristics to quantify turbulent forcing and particle properties affecting sediment resuspension, settling, and flocculation. The project links academic-level researchers directly with practitioners actively involved with several USEPA Superfund sites and indirectly with environmental researchers, engineers, and policy makers. The project will support the Ph.D. research of two graduate students who will be advised by a diverse group and trained in advanced computational fluid dynamics, acoustic and optical field instrumentation, as well as practical aspects of environmental engineering. Results from this study will link methods and results from academic research to practice, enabling application of novel methods for quantifying and predicting sediment and contaminant fate and transport to present-day contaminated sediment sites. Additionally, the PIs have worked extensively with community modeling efforts and have contributed sediment transport modules to the Environmental Fluid Dynamics Code (EFDC), a state-of-the-art hydrodynamic model in use by the USEPA. In this project, novel in-situ acoustical and optical instrument platforms will be deployed and laboratory experiments will be conducted to measure the physio-biogeochemical characteristics of flow and sediment in a turbulent, current and wave-driven shallow estuarine setting. Acoustic instrumentation will measure vertical distributions of mean flows and turbulence throughout the water column, including within the boundary layer, due to currents and waves. These will be combined with a floc camera and optical instruments that measure settling flux, particle size distributions and particulate biogeochemical compositions. Laboratory experiments will measure erosion rates and bulk densities of in-situ sediment cores. The field and laboratory observations of the sediment characteristics will be used to inform a high resolution large-eddy simulation (LES) model that resolves the details of the turbulent, sediment-laden boundary layer. The suite of data obtained from the field observations, laboratory experiments, and LES model will be used to understand the relationship between particle size distributions and turbulence in wave-driven estuarine environments and how these dynamics are affected by biogeochemical properties of the suspended particles. These dynamics will in turn be related to properties of the bed to understand how the turbulence and particle size distributions affect erosion rates. Finally, the LES model will be used to understand flocculation dynamics and the effects of sediment-induced stratification that may act to dampen the near-bed turbulence and reduce subsequent erosion and entrainment of sediment into the water column.

沉积物归宿和迁移模型常常被用来帮助解决与补救工作的环境影响、可靠的自然恢复潜力以及极端事件的潜在影响有关的环境问题。为了有效地实施沉积物归宿和输运模型，必须准确地确定河床侵蚀和沉积速率的参数。这些过程取决于物理强迫、沉积物在水柱中的分布以及沉积物的性质，如堆积密度、颗粒大小和地球化学组成。这项研究将采用高分辨率的数值模拟沿着与物理过程和颗粒特性的现场测量分析，以量化湍流强迫和颗粒特性影响沉积物再悬浮，沉降和絮凝。该项目将学术级研究人员直接与积极参与美国环保局超级基金网站的从业人员联系起来，并间接与环境研究人员，工程师和政策制定者联系起来。该项目将支持博士学位。两名研究生的研究，他们将由一个不同的小组提供咨询，并在先进的计算流体动力学，声学和光学现场仪器以及环境工程的实践方面进行培训。这项研究的结果将把学术研究的方法和结果与实践联系起来，从而能够应用新的方法来量化和预测沉积物和污染物的命运和迁移到当今受污染的沉积物地点。此外，PI广泛参与社区建模工作，并为环境流体动力学代码（EFDC）提供沉积物输运模块，这是美国环保局使用的最先进的流体动力学模型。在这个项目中，将部署新的现场声学和光学仪器平台，并进行实验室实验，以测量湍流、水流和波浪驱动的浅水河口环境中水流和沉积物的物理-地球化学特征。声学仪器将测量由于水流和波浪引起的整个水柱（包括边界层内）的平均流量和湍流的垂直分布。这些将与絮凝物照相机和光学仪器相结合，测量沉降通量，颗粒尺寸分布和颗粒物地球化学成分。实验室实验将测量现场沉积物岩心的侵蚀率和体积密度。沉积物特性的现场和实验室观测结果将用于提供高分辨率大涡模拟（LES）模型的信息，该模型可解决湍流、含沉积物边界层的细节。从现场观测，实验室实验和LES模型获得的一套数据将被用来了解在波浪驱动的河口环境中的颗粒尺寸分布和湍流之间的关系，以及这些动态是如何受到悬浮颗粒的地球化学性质的影响。这些动力学将反过来与床层的性质有关，以了解湍流和颗粒尺寸分布如何影响侵蚀速率。最后，LES模型将被用来了解絮凝动力学和沉积物引起的分层的影响，可能会起到抑制近床湍流和减少随后的侵蚀和夹带到水柱的沉积物。

项目成果

Cohesive Sediment Erosion in a Combined Wave‐Current Boundary Layer

组合波中的粘性沉积物侵蚀——当前边界层

• DOI: 10.1029/2020jc016655
• 发表时间: 2021
• 期刊: Journal of Geophysical Research: Oceans
• 作者: Egan, Galen;Chang, Grace;McWilliams, Samuel;Revelas, Gene;Fringer, Oliver;Monismith, Stephen
• 通讯作者: Monismith, Stephen

On the Variability of Floc Characteristics in a Shallow Estuary

浅水河口絮体特性的变异性研究

• DOI: 10.1029/2021jc018343
• 发表时间: 2022
• 期刊: Journal of Geophysical Research: Oceans
• 作者: Egan, Galen;Chang, Grace;Manning, Andrew J.;Monismith, Stephen;Fringer, Oliver
• 通讯作者: Fringer, Oliver

Sediment‐Induced Stratification in an Estuarine Bottom Boundary Layer

• DOI: 10.1029/2019jc016022
• 发表时间: 2020-08
• 期刊: Journal of Geophysical Research
• 作者: Galen Egan;A. Manning;G. Chang;O. Fringer;S. Monismith

Phase‐Resolved Wave Boundary Layer Dynamics in a Shallow Estuary

浅河口的相位解析波浪边界层动力学

• DOI: 10.1029/2020gl092251
• 发表时间: 2021
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Cowherd, Marianne;Egan, Galen;Monismith, Stephen;Fringer, Oliver
• 通讯作者: Fringer, Oliver

Biophysical flocculation reduces variability of cohesive sediment settling velocity

• DOI: 10.1038/s43247-023-00801-w
• 发表时间: 2023-04
• 期刊: Communications Earth & Environment
• 作者: Ye;Springer Science;Business Media;L. Ye;J. A. Penaloza-Giraldo;A. Manning;J. Holyoke;T. Hsu