Estimating discharge coefficient of triangular free overfall using the GMDH technique

Abstract Free overfalls are hydraulic structures used in flood control, water supply, irrigation, and flow measurements. The systems of free overfall depend on rectangular end shape. studies that dealt with triangular crest few almost non-existent. In this study, a end-shape design uses multiple linear regression (MLR) group method data handling (GMDH) methods for four models six sub-models. Then, 24 scenarios were chosen compared. discharge coefficient (Cd) terminal was predicted using experimental data. edge shape increased length, the coefficient, passing over overfall. To goal, 180 fall tests performed. Data collected two an opposite direction three angles 600, 750, 900. Results Cd acquired ways discussed above show algorithm GMDH outperforms other method. Values approach mod46 testing variables: RMSE, MARE, SI, R2, NSE 6.08E-17, 2.65E-17, 6.00E-17, 100.00%, 1.00, respectively, while these values MLR 0.06332, 0.05970, 0.06624, 15.431%, −3.0419, respectively. technique shows best results concerning then chooses from percentage error not exceeding ±2%.