Numerical simulation of the hydraulic performance of triangular and trapezoidal gabion weirs in free flow condition

During the recent years, gabion weirs have attracted the attention of many researchers due to their compatibility with the environment, positive effects on river's water quality and simple design and implementation. In this research, the hydraulic parameters of flow around the triangular and broad-crested gabion weirs with various side slopes were numerically investigated. The numerical results were validated using the data obtained from laboratory experiments. Overall, a number of 256 different models were studied numerically. Results indicated that decreasing the average diameter of particles may result in the reduction of the discharge coefficient (Cd), through flow discharge and the energy dissipation of flow over the models up to 27%, 34%, and 8% respectively. Also, it was concluded that the upstream slope of triangular weirs and downstream slope of broad-crested gabion weirs have more significant impact on the performance of gabion weirs. Finally, mathematical relationships are correlated using Nonlinear Multivariate regression analysis in order to estimate the discharge coefficient and through flow discharge of these structures.