عنوان مقاله [English]
Ogee crested spillways having superb hydraulic properties including simplicity in design and flow passing efficacy. So far, limited research in the area of prediction and the extraction of discharge coefficient relationship is conducted. In current study two different methods for modeling the discharge coefficient of the converging ogee spillway with a curve axis by was developed and results were compared with the observed experimental values through the Genetic Expression Programming (GEP) and artificial networks (ANNs) approaches. For this purpose, the experimental data of the Germi chay ogee spillway model with varying training wall convergence angles (), was used. Based on the obtained results, applied Artificial Intelligence (AI) models have reliable performance in predicting the discharge coefficient of converging ogee spillways. Moreover, the performance of GEP model is a bit better than ANN technique with relatively low error and high correlation values. To recognize the most effective variables on the discharge coefficient, sensitivity analysis of GEP for the best model was carried out. Results showed that ratio of the design head to the critical depth (Hd/yc) and ratio of the crest length to the downstream channel width (L/Lch) are the most and least important parameters in predicting the discharge coefficient of the converging ogee spillway respectively. The best evaluation of test series were observed in GEP approach with the values of DC=0.818 and RMSE=0.089 and in ANNs approach with the values of DC=0.77 and RMSE=0.099 which demonstrates the high accuracy of predictions.
Abbaspour, A. and Arvanaghi, H. 2011. Predicting flow over compound triangular-rectangular weir by using genetic programming. 10th Iranian Hydraulic Conference. Rasht, Iran. (in Persian)
Bazin, H. 1888. Expriences nouvelles sur l'Ecoulement par D~versoir [recent experiments on the flow of water over weirs]. Memoires et Documents. Annales des Ponts et Chaussees. Paris, France.
16, 393-448. (in French)
Cassidy, J. J. 1965. Irrotational flow over spillways of finite height. J. Mech. Eng. Div. ASCE.
Chanson, H. 2008. Physical modelling, scale effects and self-similarity of stepped spillway flows. Proceeding of the World Environmental and Water Resources Congress. May 12-16. Honolulu. Hawaii, United States.
Ferreira, C. 2001. Gene expression programming: a new adaptive algorithm for solving problems. Complex System. 13(2): 87-129.
Goel, A. 2014. Neural network technique for prediction of discharge coefficient and discharge for a weir. J. Indian Water Resour. Soc. 34(2): 25-31.
Hagan, M. T. and Menhaj, M. B. 1994. Training feed-forward networks with the Marquardt algorithm. IEEE T-Neural. Network. 5(6): 989-993.
Kia, S. M. 2014. Soft Computing in MATLAB. Qian Academic Press. Tehran. Iran. (in Persian)
Kumar, S., Ahmad, Z. and Mansoor, T. 2011. A new approach to improve the discharging capacity of sharp crested triangular plan form weirs. J. Flow Measur. Instrument. 22, 175-180.
Lopes, H. S. and Weinert, W. R. 2004. EGIPSYS: An enhanced gene expression programming approach for symbolic regression problems. Int. J. Appl. Math. Comput. Sci. 14(3): 375-384.
Menhaj, M. B. 2010. Foundations of Neural Networks. Amirkabir University Publication (Tehran Polytechnic). Tehran, Iran. (in Persian)
Morales, V., Tokyay, T. E. and Garcia, M. 2012. Numerical modeling of ogee crest spillway and tainter gate structure of a diversion dam on canar river. Ecuador, XIX International Conference on Water Resources.
Niksefat, Gh. 2001. Theoretical aspects and application of hydraulic models in hydraulic structures designing. Iranian National Committee on Large Dams, Mongograph. (in Persian)
Peterka, A. J. 1953. The effect of entrained air on cavitation pitting[C]. Proceeding of IAHR Minnesota Conference. St. Paul, USA.
Roushangar, K., Akhgar, S., Salmasi, F. and Shiri, J. 2014. Modeling energy dissipation over stepped spillways using machine learning approaches. J. Hydrol. 508, 254-265.
Shafai-Bejestan, M. 2012. Basic Concepts and Applications of Physical-Hydraulic Modeling. Shahid Chamran University Press. Ahvaz, Iran. (in Persian)
Swamee, P. K., Shekhar, C. H. and Talib, M. 2011. Discharge characteristics of skew weirs. J. Hydraul. Res. 49(6): 812-820.
Saneie, M., SheikhKazemi, J. and Azhdary, M. 2016. Scale effects on the discharge coefficient of ogee spillway with an arc in plan and converging training walls. Civil Eng. Infrastruct. J. 49(2): 361-374.