Collaborative Research: The effect of sand fraction and event evolution on fine-sediment transport and the depositional record in wave-supported mud flows

第1部分通过波浪支持的重力流(WSGC)向近海输送大陆架上的细颗粒沉积物是泥沙从源头到汇输送的关键组成部分，但人们对其知之甚少。目前这一过程的模型主要集中在泥沙和粘土大小颗粒的悬浮和输送上。然而，最近的实验室实验表明，即使是沉积层中的少量沙子也可能对输运层的动力学起主导控制作用。这项工作将研究泥沙含量对泥沙输移的影响，特别是泥沙运移方式、下坡运移和沉积特征之间的转换。这些目标将通过一系列全面的实验室实验、3D湍流解析数值模拟和WSGC在活动大陆边缘的现有现场数据的重新分析来实现。这项工作涉及广泛的领域，从流体力学和水资源工程，到生物地球化学循环的研究。外展活动包括向在大学实验室进行动手实验的K-12学生介绍沉积过程的相关性，并邀请他们向当地学校介绍情况。本科生和研究生将参与其中。除了期刊论文和会议报告外，还将通过社区表面动力学模拟系统(CSDMS)框架传播开放源码。第2部分通过波浪支持的重力流(WSGC)在大陆架上近海输送细颗粒沉积物是沉积物来源下沉的关键组成部分，但人们对其了解仍然很少。目前这一过程的模型主要集中在泥沙和粘土大小颗粒的悬浮和输送上。然而，最近的实验室实验表明，即使是沉积层中的少量沙子也可能对输运层的动力学起主导控制作用。研究了泥沙含量对泥沙输移的影响，特别是泥沙运移方式、下坡运移和沉积特征之间的转换。该项目围绕两个主要目标形成：1)确定砂组分在控制WSGC内部的动力学和输送以及与之相关的床层沉积方面的作用。2)评估事件演变(风暴的激增和减弱)对重力流中沉积物和流动动力学的影响以及由此产生的沉积特征。这些将通过一系列全面的实验室实验、3D湍流解析数值模拟和对WSGC在活动大陆边缘的现有现场数据的重新分析来解决。这项工作涉及广泛的领域，从流体力学和水资源工程，到生物地球化学循环的研究。外展活动包括向在大学实验室进行动手实验的K-12学生介绍沉积过程的相关性，并邀请他们向当地学校介绍情况。本科生和研究生将参与其中。除了期刊论文和会议报告外，还将通过社区表面动力学建模系统(CSDMS)框架传播开放源码。

Part 1Offshore delivery of fine sediment on the continental shelf via wave supported gravity currents (WSGC) is a key component of sediment transport fromsource to sink, yet it remains poorly understood. Current models of this process focus on suspension and transport of silt and clay sized particles. However, recent laboratory experiments show that even a small amount of sand in the sediment layer may exert a dominant control on the dynamics of the transport layer. The proposed effort will investigate the effect of sand fraction on sediment transport in WSGC, particularly, the transition between transport modes, the downslope transport and the depositional signatures. The objectives will be addressed using a comprehensive series of laboratory experiments, 3D turbulence-resolving numerical simulations, and re-analysis of existing field data from WSGC on active continental margins. The work is relevant to a broad range of fields, from fluid mechanics and water resource engineering, to studies of biogeochemical cycles. Outreach include introduction of the relevance of sedimentary processes to K-12 students with hand-on experiments in the university labs, and invited presentations to local schools. Undergraduate and graduate students will be involved. In addition to journal papers and conference presentations, open-source codes will be disseminated through Community Surface Dynamics Modeling System (CSDMS) framework.Part 2Offshore delivery of fine sediment on the continental shelf via wave supported gravity currents (WSGC) is a key component of sediment source to sink, yet it remains poorly understood. Current models of this process focus on suspension and transport of silt and clay sized particles. However, recent laboratory experiments show that even a small amount of sand in the sediment layer may exert a dominant control on the dynamics of the transport layer. The proposed effort investigates the effect of sand fraction on sediment transport in WSGC, particularly, the transition between transport modes, the downslope transport and the depositional signatures. The project is formed around two main objectives: 1) Determine the role of the sand fraction in controlling dynamics and transport within WSGC and the bed deposits associated with them. 2) Evaluate impacts of event evolution (surging and waning of a storm) on the sediment and flow dynamics within a gravity flow and the resulting depositional signatures These will be addressed using a comprehensive series of laboratory experiments, 3D turbulence-resolving numerical simulations, and re-analysis of existing field data from WSGC on active continental margins. The work is relevant to a broad range of fields, from fluid mechanics and water resource engineering, to studies of biogeochemical cycles. Outreach include introduction of the relevance of sedimentary processes to K-12 students with hand-on experiments in the university labs, and invited presentations to local schools. Undergraduate and graduate students will be involved. In addition to journal papers and conference presentations, open-source codes will be disseminated through Community Surface Dynamics Modeling System (CSDMS) framework.