Experimental and Numerical Investigation of Flow Measurement Mechanism and Hydraulic Performance on Curved Flume in Rectangular Channel

Abstract

For decreasing the head loss of flume, three curved flumes were presented based on principle of critical flow. And a serial of laboratory experiments cooperating with numerical simulations was performed based on the designed flumes, the hydraulic performances such as water depth, free-surface velocity obtained from experiments and simulations were analyzed, the comparison indicates that the maximum relative error of water depth is 4.7%, a good agreement between simulation results and experimental values was obtained. On this basis, the distribution of velocity, upstream depth, Froude number and head loss of three curved flumes were analyzed with simulated data, the results showed that the velocity increased at the contraction section, and kept increasing to a maximum at the latter part of the throat section under free flow condition, finally, decreased rapidly under submerge flow condition. With the increase in contraction ratio, the upstream depth, Froude number proposed decreased and increased trend, respectively. The head loss decreased with the increasing of contraction ratio, the maximum of head loss is 38.4% with a contraction ratio of 0.4 when the flow rate is 26.41 L/s, smaller than other flume. Further, a formula which was demonstrated a high accuracy for calculating the discharge of the curved flumes were derived based on the principle of dimensional consistency. The presented curved flume has less head loss and higher measurement accuracy, and can be applied to flat and gentle slope channels, which contributes to the sustainable development of agriculture water utilization.