Investigation the Stage- Discharge Relationship and Discharge Coefficient in Sharp-Crested Weirs with Triangular Shape in Plan

The triangular in plan sharp-crested weirs do not have a direct and straight edge and are in good agreement with the broken line. The aim of the present study is to provide an equation for discharge coefficient (Cd) for these types of weirs. Cd is between 0.53-0.88 based on the observed data. For =15 degrees Cd has highest value and thus weir can convey maximum discharge. Using laboratory data based on h/p and α parameters, a regression equation was presented. The results of the regression equation were compared with the results of the numerical model (Ansys Fluent) and the results showed the high precision of this equation. Ansys Fluent software works based on finite volume method. The numerical simulation is 3D. In addition, the performance of MR-Linear and MR-nonlinear regression models on the application of the stage-discharge equation the triangular in plan sharp-crested weirs were investigated and indicated that the result of this equations is very similar to results of the experimental data. The results also showed that due to the angle of the triangular in plan sharp-crested weirs, the Cd is increased from 1 to 8 % to the suppressed weir. In a situation where the head on the crest of these weirs is low, they will show better performance.