Sanaz Shoaie - Postgraduate Student, Department of Civil Engineering, Faculty of Eng., Kharazmi University, Tehran, Iran
Mojtaba Mehrain - Assistant Prof.Department of Civil Engineering, Kharazmi University, Tehran, Iran

Nowadays, due to the significant development of hydraulic models, it is possible to investigate hydraulic phenomena and reveal the extent to which their changes in a particular parameter will affect the flow condition without the need of extra experiments. In the present study, flow patterns over a side orifice were studied both experimentally and numerically. The accuracy and ability of the response surface methodology (RSM), especially central composite design (CCD), to describe the hydraulic performance flow through side orifice is validated using experimental data. RSM-CCD is an appropriate method to design the required runs and decreases the required number of simulations as compare to the previous researches in this field of research.The results indicate that like the traditional methodology, RSM-CCD introduces an acceptable model of the side orifice, but it requires a much lower number of experiments. In this study, the streamlines in three levels such as the lower crest level, upper crest level and near water surface level are studied. A stagnation zone is detected in the lower crest level. The zone forms due to the deviation of the streamlines to the side orifice.

Numerical simulation, hydraulic models, central composite design (CCD), response surface methodology