Hydraulic characteristics and flow measurement performance analysis of portable fish-shaped flumes in U-shaped channels

Achieving accurate flow measurement in small channels is important to improve water use efficiency and reduce agricultural water waste. Commonly used fixed flumes have the disadvantages of high construction cost and easily causing local deposition in channels resulting in large measurement errors. There are no such disadvantages fixed type flumes in portable measuring flumes. However, portable flume types are less commonly used, and have not been widely applied. In this study, a streamlined portable fish-shaped cylinder (the plane figure is fish-shaped) was designed for flow measurement based on bionics and critical flow measurement principles. Prototype and numerical simulation experiments were conducted to study the hydraulic characteristics of the fish-shaped flume in U-shaped channels, which were under conditions of different discharges, slopes and contraction ratios. The hydraulic characteristics and flow measurement performance of the portable fish-shaped flume in the U-shaped channels were analyzed. The results showed that the numerical simulation results based on the RNG k-epsilon three-dimensional turbulence model were in good agreement with the prototype experiment. This study demonstrates that the proposed portable fish-shaped flumes can be used for flow measurement in small channels with the advantages of high measurement accuracy, high portability, small head loss, small upstream turbulence, and high submergence degree.