分层植被水流中物质输运初始阶段的垂向混合过程

Mixing process in the layered vegetation flow plays a fundamental role in various applications such as water ecology protection. Existing researches have mainly focused on the longitudinal and lateral mixing processes in the longtime stage, leaving the vertical mixing process in the initial stage to be thoroughly explored. The present project aims to explore the vertical mixing process in the initial stage through both experimental and theoretical studies. Firstly, to conduct a series of flume experiments with flow structure and vertical concentration measured respectively. Secondly, to analytically construct the vertical dispersion coefficient and determine its variability in different layers. Lastly, to solve the advection-dispersion equation and give the theoretical solution of vertical concentration distribution, and to explore its longitudinal evolution. Meanwhile, to investigate the vertical mixing process under the conditions of coherent vortex, turbulent diffusion, as well as the vegetation structure including density, submergence and arrangement. The results should provide useful information to further understand the vertical mixing process in the initial stage of mass transport in the layered vegetation flow, and to protect the water ecology.

分层植被水流中的物质混合过程对水生态保护等领域至关重要。目前的研究局限于探讨物质释放长时间后的纵向和横向混合过程，而对初始阶段垂向混合过程的研究还不够深入。本项目针对分层植被水流中物质输运初始阶段的垂向混合过程，通过多种工况条件下的水槽试验，结合理论分析，建立垂向离散系数公式，阐明垂向离散系数在不同层的变化规律和主导机制，解析求解对流-离散方程，得到垂向浓度分布的表达式，揭示垂向浓度分布及其沿程演化规律，同时探讨混合层相干涡强度和入侵深度、湍流扩散，以及植被结构包括密度、淹没深度、布置方式等因素对垂向混合过程的作用机理。本项目综合运用试验测量和理论分析手段，研究分层植被水流中物质输运初始阶段的垂向混合过程机理，可为生态河道建设和水生态修复等提供科学依据。

分层植被水流中的物质混合过程对水生态保护等领域至关重要。目前的研究局限于探讨物质释放长时间后的纵向和横向混合过程，而对初始阶段垂向混合过程的研究还不够深入。本项目针对分层植被水流中物质输运初始阶段的垂向混合过程，运用理论分析和水槽实验测量相结合的方法，建立了物质输运初始阶段的离散系数公式，获得了二维浓度分布及演化模型，揭示了植被结构对物质离散过程的影响规律。本项目综合运用试验测量和理论分析手段，研究分层植被水流中物质输运初始阶段的垂向混合过程机理，可为生态河道建设和水生态修复等提供科学依据。