项目名称： 波流悬沙输移对多尺度紊动结构的响应机制

项目编号： No.51509168

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 其他

项目作者： 李寿千

作者单位： 水利部交通运输部国家能源局南京水利科学研究院

项目金额： 20万元

中文摘要： 我国河口海岸边界地形复杂、岛屿众多，且底床多为细粉沙所覆盖，在波流作用下泥沙易于起动、悬浮和输移，且床面常伴有一定尺度的沙纹，底部水流的涡动力结构又进一步增强了泥沙的悬浮，形成动力、边界及泥沙三个过程相互反馈系统。该系统存在波浪所致全水深范围的低频波动、沙纹所致底部低频涡动及水体运动所致全水深范围高频脉动等多时空尺度的紊动结构（广义），其对悬沙输移的作用机制仍不明晰。.拟采用理论分析与水槽试验结合，开展波流多尺度紊动结构特征、边界层内外时均流速分布特征及悬沙分布特征的研究，揭示多尺度紊动结构的形成和演化机理，辨析不同时空尺度的紊动结构对时均流剖面及含沙量剖面的驱动机制，建立波流共同作用下波动、涡动及脉动分布表达式，边界层内外时均流分布统一表达式，时均含沙量分布及临底含沙量表达式。为提高河口海岸工程泥沙预报精度提供理论基础。

中文关键词： 波流；悬沙输移；多尺度；紊动结构

英文摘要： Estuaries and coasts in China are always characterized by complex boundary conditions, lots of islands and bed materials of silt. Under co-action of combined waves and currents, silt is easily in incipient and suspension. Moreover, sand ripples formed on the bed, vortex structures developed in the bottom currents, and further enhance sediment suspending, exhibiting a fluid-boundary-sediment interactive system. This system comprises of wave induced fluctuation, ripple induced vortex motion and the real high frequency turbulence, which can be defined as generalized turbulence with multi-scales. Its influence on suspended load transport is still not well known..By theoretical analysis, and flume experiment, this project mainly investigates the characteristics of multi-scale turbulence structure, time averaged velocity profile and time averaged suspended concentration profile under co-action of combined waves and currents, and try to reveal the formation and evolution mechanism of the multi-scale turbulences and distinguish the driving mechanism of multi-scale turbulences to time averaged velocity profile and concentration profile. In addition, formulas for distribution of fluctuation, vortex motion and real turbulence, time averaged velocity, and concentration will be derived. It would provide a theoretical basis for improving the precision of sediment transport prediction with coastal engineering.

英文关键词： combined waves and currents;suspended load transport;multi-scale;turbulence structure