Experiment and numerical simulation on hydraulic characteristics of novel trapezoidal measuring weir
GAO Feifei1, LI Xiaoqing1,2*, GAO Qiang1
1. College of Water Conservancy and Civil Engineering, Xinjiang Agricultural University, Urumqi, Xinjiang 830052, China; 2. Xinjiang Key Laboratory of Water Resources Engineering Safety and Water Disaster Prevention, Urumqi, Xinjiang 830052, China
Abstract：Trapezoidal measuring weir is widely used in the end channels of irrigation area because of its simple structure and high flow measurement accuracy. However, the existing trapezoidal measuring weir in irrigated areas has the problems of small flow measurement range and easy deposition of sediment in front of the weirs, which seriously restrict its application and popularization. Therefore, based on the improved standard weir, a new type of trapezoidal measuring weir was proposed. Dimensional analysis method was used to determine the basic pattern of flow formula. Based on the results of hydraulic model experiment, numerical simulation model parameters are calibrated. The water depth, weir flow value, velocity distribution and velocity vector diagram of four new trapezoidal measuring weirs under different flow conditions are obtained by using Fluent software. Finally, the flow measurement formula is fitted by the experiment data. The result shows that the influence of the orifice outflow of the new trapezoidal measuring weir with different orifice heights on the outflow of the weir decreases with the increase of the total head in front of the weir. The fitted flow formula is simple and easy to use, with an average relative error about 2.63%. By comparing the simulation results and that of expe-rimental results, it is found that they are in high degree of agreement with average relative error of 2.53%, which indicating that the simulation results have a certain reliability, and can provide basis for engineering design of weir hole combined water measuring facilites.
