Study of the hydraulic characteristics of an airfoil-shaped weir trough measurement and control integrated facility combined with numerical simulation

Abstract

In this study, an integrated measurement and control facility with an airfoil weir as the primary overcurrent structure is proposed by considering the flow characteristics over different shapes of weir trough facilities as well as the approach of merging measurement and control functions. The incomplete self-similarity theory and dimensional analysis are used to derive the stage-discharge relationship. The hydraulic characteristics of the facility under different shape-related parameters, weir crest heights (rotation angles), and flows are studied by combining model testing and numerical simulation. The findings demonstrate that changes in shape- related parameters and rotation angle do not affect the linear relationship between the water depths in the critical and reference sections. The mean error in the discharge formula derived by dimensional analysis is 2%. The Froude number is less than 0.25 under all the working conditions. From the backwater height and head loss, it can be seen that the larger the P/C (the maximum airfoil thickness P to the chord length C ratio) value of the facility under the premise of unifying the weir crest height, the better the overflow capacity. When the height of the weir crest is 0.3778 m, the negative pressure on the surface of the airfoil weir increases with increasing P/C value.