底部倒灌异重流运动特性试验研究

Experimental study of motion characteristics of a bottom intrusion density flow

以三峡水库支流库湾广泛存在的倒灌异重流为背景,构建室内物理模型,以入流量、初始水位、温度差3个主要影响因子,设计系列工况对底部倒灌异重流运行特性进行模拟试验研究,分析异重流头部移动速度、交界面高度、头部厚度等主要水力学要素的变化过程及受入流量、初始水位、温度差的影响规律.研究表明底部倒灌异重流头部移动速度沿程呈线性递减,头部交界面沿程呈线性升高,头部厚度沿程呈线性递减.异重流运动稳定后,同一断面处,异重流头部速度随入流量、初始水位及温差的增加而增大,交界面高度随入流量及初始水位的增大而升高;异重流头部厚度受初始水位变化影响最敏感,随初始水位升高而增加.

With the background that widespread intrusion density flow are witnessed in the tributary bays of Three Gorges Reservoir,an indoor physical model was built,and three main factors including inflow rates,initial water level,temperature difference were chosen to design series of conditions to simulate and study the characteristics of the bottom intrusion density flow.The hydraulic processes of the density flow such as the head moving speed,interface height and head thickness and the influencing laws were analyzed.The results show that the head moving speed of the bottom intrusion density flow decreases linearly along the process,and the same the process of the thickness of the head along the way as the same,while the head interface increases linearly.After the density flow stabilized,at the same section,the head moving speed and the interface height increases with the inflow,the initial water level and the temperature difference;the thickness of the head increases most sensitively with the initial water level.