Optimization of ANFIS network using firefly algorithm for simulating discharge coefficient of side orifices

Side orifices are installed on side walls of the main channel to regulate and measure the flow. Generally, discharge coefficient is the most important hydraulic parameter of side orifices. In this study, using ANFIS and firefly algorithm, discharge coefficient of rectangular and circular side orifices was simulated. Firstly, effective parameters were defined then six ANFIS and ANFIS-FA models were introduced. Monte Carlo simulations were utilized to survey the ability of numerical models, and the k-fold cross-validation approach was used to validate numerical results. Then, a sensitivity analysis was employed to introduce the superior model. The superior model predicted discharge coefficient with reasonable accuracy. This model estimated discharge coefficient in terms of all input variables. For example, for ANFIS model, R and SI were computed 0.832 and 0.029, respectively. In addition, for the hybrid model, RMSE, MARE and SI were calculated as 0.017, 0.017 and 0.027, respectively. Additionally, the ratio of width of the main channel to the side orifice diameter (B/D) was identified as the most effective parameter.