Sohrab karimi - M.Sc.Student, Department of Civil Engineering, RaziUniversity, Kermanshah, Iran
Hossein Bonakdari - Associate Professor, Department of Civil Engineering, Razi University, Kermanshah, Iran
Isa Ebtehaj - Ph.D. Candidate, Department of Civil Engineering, Razi University, Kermanshah, Iran
AmirHossein Zaji - Ph.D. Candidate, Department of Civil Engineering, Razi University, Kermanshah, Iran

Diversion channels are widely used in environmental and hydraulic engineering. One of the important issues in designing such channels is to determine the mean velocity or the discharge of the flow passing through them. The aim of this study is to predict the flow mean velocity in different widths of the intake channel (the branch channel width to the main hannel) through the use of Gene Expression Programming (GEP). Taking into consideration the fact that the experimental results are available forone width ratio, the experimental model of an intake has first been simulated for a similar width ratio in the channel (W*b/W*m=1)through three dimensional modeling. The results of the carried out verification MAPE=5% RMSE=0.017) indicates the significant accuracy of the results obtained from the three dimensional modeling. Following that the numerical model was executed for (W*b/W*m=0.6, 0.8, 1.2, 1.4) width ratios in order to redict the flow mean velocity in other width ratios and a part of the numerical results were considered as the input of GEP and another part was used to verify the used model. The results of the statistical indexes used to xamine the accuracy of this model quantitatively (RMSE=0.0231 & MAPE=5.54) indicate the high accuracy of the presented model in prediction the flow mean velocity in an open channel intake.

Diversion channels, the mean velocity,different widths,Gene Expression Programming