This study investigates the impact of groove implementation on the hydraulic performance of sharp-edged trapezoidal side weirs, focusing on discharge coefficients and shear stress behavior. The simulation processes were carried out using the VOF (Volume of fluid) methodology in combination with the RNG (Re-normalize group) model for turbulence. The validation with experimental data by comparison showed that the relative error in the range of 0.4-2.6%. It was found from the results that the discharge coefficient increases in the no-grooved model and decreases in the grooved model. The identified variation of the discharge coefficient range through different Froude numbers lies between 0.6 and 0.8, where the discharge coefficient of the no-grooved model is larger by 2.68% compared to that of the grooved model. The grooved model was more effective for lower flow rates, while the no-grooved model was more effective for higher flow rates. In all cases, in both models, the discharge coefficient increases with the Froude number, with a greater increase observed in the no-grooved configuration (19.64% higher). The research indicated that grooves significantly reduce shear stresses at the crest of the weir, reducing further damage to the structure. The variation in shear stress between the two models was most evident under high flow conditions, demonstrating the efficiency of the grooved model in reducing harmful stresses and energy dissipating.
