涌潮作用下泥沙再悬浮通量变化研究

It is a complex process for sediment resuspension under tidal bores, which involves the interaction between tidal bores and high sediment concentration at the bottom. Material migration and circulation are closely related to sediment resuspension. It will enhance the insight of the veritical movement by studying the variation of sediment resuspension flux in tidal bores. In order to investigate the mechanism of sediment resuspension under tidal bores, this project intends to study the variation of sediment resuspension flux and exhibit the exchange mechanism betwwen the river and suspended sediment on the basis of the theoretical analysis from the field observation and flume experiment. The bottom shear stress, the variation of high sediment concentration, the rate of sediment exchange and the calculation method of sediment resuspension flux will be investigated. It will be started from the hydrodynamics of tidal bore and the exchange characteristics to analyze the interaction between tidal bores and sediment particles and reveal the vertical feature of sediment movement by investigating the lift of tidal bores and sediment resuspension flux. The research results will not only provide calculation basis for the establishment of three-dimensional sediment model in a tidal bore estuary, but also promote the development of the relative disciplines in a macro-tidal estuary.

涌潮作用下泥沙再悬浮过程复杂，其涉及到涌潮水流和底部高含沙层的相互作用。涌潮河口物质迁移和循环均与再悬浮作用有着紧密的关系，对泥沙再悬浮通量变化研究有助于深刻认识涌潮强紊动作用下物质的垂向运动。为阐明涌潮作用下泥沙再悬浮机制，本项目拟基于现场实测数据的理论分析，通过水槽试验对涌潮作用下泥沙再悬浮通量变化进行研究，给出涌潮掀沙下床沙交换机理。项目主要研究涌潮作用下底部应力、高含沙层的变化、床沙交换速率和泥沙再悬浮通量的计算方法。从涌潮动力和床沙交换特征出发，通过对涌潮掀沙机理和泥沙再悬浮通量的研究，分析涌潮和泥沙的相互作用，揭示涌潮掀沙下泥沙垂向运动特征。研究成果将为涌潮河口泥沙三维数学模型的发展提供计算依据，促进强潮河口相关学科的发展。

本项目分析了涌潮作用下泥沙再悬浮过程涉及到涌潮水流和底部高含沙层的相互作用，通过现场实测数据、水沙数学模型和水槽试验等多种手段研究了涌潮水流、涌潮作用下高含沙层的变化、床沙交换速率，给出了涌潮作用前后泥沙悬浮通量的变化。从涌潮动力和床沙交换特征出发，通过现场实测数据对涌潮掀沙机理和泥沙再悬浮通量的研究，分析了涌潮和泥沙的相互作用，给出了涌潮掀沙过程中含沙量和泥沙粒径等变化，为再悬浮通量计算方法的确定提供依据。通过模型试验对涌潮掀沙下河床泥沙交换进行研究，为涌潮作用下床沙交换速率的确定提供计算手段，给出涌潮河口的床沙交换机理。对涌潮作用下泥沙再悬浮过程进行研究，分析涌潮水流和高含沙层的变化规律，给出涌潮掀沙下泥沙垂向运动特征。在涌潮到达时刻含沙量和瞬时泥沙通量相当于到达前一个量级，涌潮作用下床沙交换速率达到其它海域的一个量级以上，远大于其它海域床沙交换速率。在涌潮河口三维泥沙数学模型的计算中采用涌潮作用下床沙交换速率进行悬浮通量的计算，可模拟涌潮输沙过程。在项目执行期间，共参加学术会议4次，发表论文8篇，获得专利1项。