Enhancing the discharge capacity of contracted weirs using novel models

This study utilizes three-dimensional Computational Fluid Dynamics simulations to investigate the implementation of stepped and diagonal platforms as a means to enhance the discharge capacity of contracted sharp-crested weirs. Using numerical models validated against experimental data, various stepped and diagonal shifted configurations were compared to traditional rectangular slit weirs. The results demonstrate that these advanced geometries significantly outperform standard designs, increasing discharge efficiency by up to 30% across all nappe heads. While extended crest lengths drive this enhanced performance, increasing the number of steps introduces nappe interference at the corners, which can negatively impact the discharge coefficient. Furthermore, flow field analysis reveals that although these configurations improve discharge per unit channel width, asymmetrical vortices and streamline contractions may reduce efficiency per unit crest length. Ultimately, the study confirms that the proposed flow-area-based dimensionless parameter effectively characterizes hydraulic constraints, proving that stepped and diagonal designs offer a viable solution for enhancing weir capacity in hydraulic engineering.