Mean Velocity Measuring Point of Semi-circular Open Channel Section Based on Flow Partitioning Theory北大核心CSCD

【Objective】The purpose of this paper is to reveal the characteristic position of the mean velocity along the normal line of the semi-circular channel wall and provided a novel method for flow measurement in non-uniformed channel, the physical model experiments were conducted in semi-circular channel.【Method】Based on the measuring results of flow velocity under different hydraulic conditions, the theoretical formula for calculating the mean velocity characteristic position along the normal line of the semi-circular channel wall was derived from flow partitioning theory. Considering the influence from side wall to friction velocity, the mean flow velocity of the entire semi-circular channel section can be obtained by measuring the flow velocity at the characteristic location.【Results】This paper proposed the theoretical formula and the measurements achieved a good agreement within 10% error. The formula can clearly reflect the distribution of the semi-circular open channel well. The velocity distribution should be analyzed along the normal line，thus the analysis methods was more reasonable. 【Conclusion】The theoretical results on determining mean velocity characteristic position fitted well the results from experiment and it indicated the formula has higher precision. The flow velocity at a specific position can be measured to further estimate the mean flow velocity of the section, so as to quickly and accurately determine the flow rate of the channel section in the project. © 2019 Journal of Irrigation and Drainage. All rights reserved.