rectangular channel, rudder-like measuring flume, numerical simulation, streamline shape, Agriculture (General), S1-972, Irrigation engineering. Reclamation of wasteland. Drainage, TC801-978

【Objective】 Flume is a hydraulic device widely used in hydraulic engineering projects. Its performance depends on many factors. In this paper, we explore the alignment of measuring flume with smooth flow, stable flow pattern, accurate flow measurement and small head loss, based on the streamline structure of underwater equipment. 【Method】 Four flumes with different streamline shapes were studied. Numerical simulation was used to study their hydraulic performance under different flow rates, including velocity distribution, water surface profile, Froude number, water head loss and backwater height. 【Result】 It is found that the backwater height of the flume and the head loss both decreased when the diffusion became steeper. The upper Froude numbers of the four flumes were less than 0.5, regardless of the flow rates. The backwater heights were less than 3 cm. The average error between the measured and simulated flow rate was less than 2.42%, indicating that the flow measurement is accurate, and the head loss is small. 【Conclusion】 The water surface profile of the KKS type flume is more stable, and the velocity distribution is more uniform under different flow rates, compared to other flumes. Its head loss is less than 0.35 cm, the flow measurement accuracy is more than 98.27%. Its hydraulic performance is hence the best among the flumes we compared.