Different experiments and numerical simulation research were carried out in order to explore the hydraulic characteristics and applicability of the cutthroat flume, NACA airfoil-shaped flume, airfoil pillar-shaped flume, and optimized airfoil-shaped flume in rectangular channels. The four flumes with contraction ratios of 0.4, 0.5, and 0.6 in rectangular channels were tested under 144 free-flow conditions. Based on the Fluent software, standard k-ε three-dimensional turbulence model and volume of fluid (VOF) method were utilized for numerical simulation in each working condition. The principle of critical flow was used to analyze the correlation between the discharge, the contraction ratio, and the upstream water depth. This correlation was used to obtain the discharge calculation formulas of the cutthroat flume, NACA airfoil-shaped flume, airfoil pillar-shaped flume, and optimized airfoil-shaped flume in rectangular channels. The Froude number in front of the flume, the backwater height, the critical submergence degree, the velocity distribution, the head loss, the discharge measurement formula, and the accuracy were studied and compared. It can be concluded from the results that the cutthroat flume, NACA airfoil-shaped flume, airfoil pillar-shaped flume, and optimized airfoil-shaped flume all have good applicability in rectangular channels. Moreover, the hydraulic characteristics of all the four flumes meet the water measurement specifications in the irrigation area. The upstream Froude number of the NACA airfoil-shaped flume is the smallest, whereas the backwater height and head loss of the cutthroat flume and optimized airfoil-shaped flume are the smallest. It is also worth noting that the critical submergence degree of the optimized airfoil-shaped flume is the highest, with an average value of 0.85. The discharge measurement formulas of the four flumes have been deduced using the correlation between the discharge, the contraction ratio, and the upstream water depth. It was found that the average errors between the calculated discharge and the measured discharge of the four flumes are 3.17%, 2.17%, 1.53%, and 2.29%, respectively, which are less than 5%, and therefore meet the discharge measurement requirements. In the agricultural irrigation system and flow monitoring system, the hydraulic characteristics of the four flumes can provide a reference and basis for the selection of flumes in the rectangular channel.

通过不同的试验和数值模拟研究，探讨了喉式水槽、NACA翼型水槽、翼型柱状水槽和优化的翼型水槽在矩形通道中的水力特性和适用性。在 144 种自由流动条件下对矩形通道中收缩率为 0.4、0.5 和 0.6 的四个水槽进行了测试。基于Fluent软件，采用标准k-ε三维湍流模型和流体体积（VOF）方法对各工况进行数值模拟。临界流量原理被用来分析流量，收缩率和上游水深之间的关系。利用该相关性得到了喉咙水槽、NACA 翼型水槽的流量计算公式，翼型柱状水槽，优化了矩形通道中的翼型水槽。对水槽前的弗劳德数、回水高度、临界淹没度、流速分布、水头损失、流量测量公式及精度进行了研究和比较。由结果可以得出，割喉槽、NACA翼型槽、翼型柱状槽、优化翼型槽均在矩形通道中具有良好的适用性。此外，四个水槽的水力特性均满足灌区测水规范。NACA翼型水槽上游弗劳德数最小，喉口水槽和优化翼型水槽的回水高度和水头损失最小。还值得注意的是，优化后的翼型水槽临界浸没度最高，平均值为0.85。利用流量、收缩率和上游水深之间的相关性，推导出了四个水槽的流量测量公式。发现4个水槽计算流量与实测流量的平均误差分别为3.17%、2.17%、1.53%和2.29%，均小于5%，满足流量测量要求。在农业灌溉系统和流量监测系统中，四个水槽的水力特性可以为矩形渠道水槽的选择提供参考和依据。