U形渠道机翼形量水槽水跃数值模拟与试验研究

Numerical simulation and experimental research of hydraulic jumps on the airfoil-shaped measuring flume in U-shaped canal

量水槽是灌区常见的特设量水设备,而槽后水力特性是判断其选型是否合理的重要指标之一。以某小型灌区末级灌溉渠系改造工程为原型,针对两种不同工况,采用基于TruVOF方法跟踪自由液面、Favor技术实现网格优化的湍流数学模型,对U形渠道机翼形量水槽水跃问题进行三维数值模拟,分析了水跃的时均流场、共轭水深、发生位置、跃长、断面流速分布以及水跃段能量损失等相关水力特性。采用与原型1∶1比尺的水工模型试验资料对模拟结果进行验证,结果表明,二者吻合较好。通过对实测与数值仿真的共轭水深数据进行统计分析,得到了适用于U形渠道机翼形量水槽水跃共轭水深的近似计算公式。研究结果对机翼形量水槽在平原缓坡灌区末级渠系的应用研究提供了一定的参考和建议。

Measuring flume is a common water measuring device which is designed for irriga- tion. The characteristics of hydraulic jump is one of the important indexes to judge whether the selected shape is suitable. This paper discussed the last stage of irrigation canal renovation project in a certain small irrigation area as an archetype, with two different experimental conditions, computed by the turbulence mathematical model tracking the free surface of liquid based on Tru- VOF method and realized mesh optimization based on Favor. We also simulated the water jump in U-shaped canal airfoil-shaped flume in three dimensions, and analyzed the hydraulic characteris- tics such as time-averaged flow field, conjugate depth, occurring position, jump length, distribu- tion of hydraulic velocity in cross section and the loss of energy of hydraulic jump section. We verified simulation results by using experimental data of hydraulic model test whose ratio arche- type is 1：1. The results of experimental and the computational model are consistent. In the end, we analyzed the conjugate depths of experimental data and simulation results, and inferred the ap- proximate calculation formula of conjugate depths for U-shaped canal airfoil-shaped flume. This research provides some basic advice and suggestions on the application of airfoil-shaped flume in irrigated area in last stage of canal system in plain with gentle slope.