中文摘要：

利用计算流体力学商业软件FLUENT,建立了含采砂坑明渠立面的二维数学模型,其中,封闭方程采用标准k~ε模型的紊流方程,自由表面采用Volume of Fluid（VOF）方法模拟.在与明渠水流实验数据对比的基础上,研究了不同矩形采砂坑长度、深度和面积对明渠水位降低的影响.结果表明：当采砂坑面积相同时,长深比越大,水位降落越明显,长度的增加对水位跌落影响较大;随着采砂坑深度、长度增大,水位降落呈现缓慢增加、急剧增大和再平缓增大3个阶段,对应的单位坑深、局部水头损失呈现急剧上升、急剧下降、缓慢下降3个阶段.

英文摘要：

A vertical 2D mathematical model for the rectangular sandpit in the open channel was established by using the computational fluid dynamics commercial software FLUENT.The k-ε model was used for turbulent closure and the volume of fluid（VOF） method was employed to simulate the free surface in the open channel.Based on comparison with the experimental data,the effects of the lengths,depths,and areas of different rectangular sandpits on the water level in the open channel were analyzed.The results show that with a constant area of sandpit,the larger the length-depth ratio is,the more significantly the water level drops,and greater the effect of the increase of length on the drop of the water level.With the increase of the depth and length of the sandpit,the dropping process of the water level can be classified into three stages： the slowly increasing stage,the rapidly increasing stage,and the gently increasing stage;while the corresponding per unit depth of sandpit and local head loss have three stages： the rapidly increasing stage,the rapidly decreasing stage,and the slowly decreasing stage.