Most previous studies have focused on adjustable complex flap gates and little researches has been carried out on simple inline top-hinged plates for flow measurement. The present study investigates discharge measurement by top-hinged plates located along channels under free flow condition. The proposed simple device is a portable one. Two discharge models are proposed based on Buckingham's theorem of dimensional analysis. The first model (Model I) considers deflection angle as an independent variable while the second model (Model II) considers it as a dependent variable. A series of laboratory experiments (687 runs) were performed to calibrate the proposed models. The results showed that when the slope of the channel increases, the accuracy of the proposed model slightly decreases. The first model has an average error of 2.32%, while the second model has an average error of 3.19%, thus flow discharge through the rectangular channels with longitudinal slopes in range of [0, 0.005] can be accurately estimated using the proposed discharge models. Based on this experimental study, the plate length enhances the performance of the second model when the mass plate is unknown. The proposed device offers a simple and reliable discharge measurement approach for both horizontal and sloping rectangular channels.

  • Portable top-hinged plate is studied as a simple and low-cost water measuring device.

  • Experiments is performed to formulate discharge of in-line top-hinged plate.

  • Effects of the channel slope, and plate width are investigated.

  • Extensive error analysis presents for developed general discharge relations.

  • The proposed discharge relations are general, accurate and simple.

Graphical Abstract

Graphical Abstract
Graphical Abstract
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