Evaluating energy dissipation in through gabion sills under free and submerged hydraulic jump conditions using numerical simulation

• Advanced Modeling of Hydraulic Jumps : The study uses the FLOW3D model to accurately simulate energy dissipation in hydraulic jumps over gabion sills, demonstrating the model's capability in capturing complex flow dynamics under both free and submerged conditions. • Optimized Performance Metrics : Through rigorous calibration, the study achieves high accuracy, with error metrics such as RMSE as low as 0.0147 and R² values exceeding 0.99, validating model's predictions against experimental data. • Key Insights on Energy Dissipation : The research identifies the influence of gabion granulation, sill height, and positioning on energy dissipation, with findings showing up to 70% dissipation in free jumps and up to 60% in submerged conditions under optimal configurations. This study applies the FLOW3D numerical simulator to predict energy dissipation across gabion sills in free and submerged hydraulic jump conditions downstream of an ogee spillway. FLOW3D was rigorously calibrated and verified, showing high accuracy in modeling complex flow dynamics. The model’s performance was optimized by selecting the M7 mesh configuration and the RNG (k-ε) turbulence model, achieving error metrics that align closely with experimental data: RMSE of 0.0147 and MAE of 0.0092 with R² = 0.993 for free jumps, and RMSE of 0.0236 and MAE of 0.0155 with R²=0.9959 for submerged conditions. Simulated predictions indicated maximum energy dissipation of 70% under free jump conditions with fine gabion granulation, decreasing to 50% with coarser materials. For submerged jumps, energy loss predictions reached 60% at an optimal sill height and position, with the model accurately reflecting decreased dissipation as gabion size increased. FLOW3D’s robust performance and high correlation with empirical findings underscore its potential as a reliable tool for modeling hydraulic jumps and optimizing energy dissipation designs in hydraulic structures.