Document Type : Research Paper


1 Department of Water Science and Engineering, Faculty of Agriculture, Bu-Ali Sina University, Hamadan, Iran.

2 Department of Water Engineering, Faculty of Agriculture, Kermanshah Branch, Islamic Azad University, Kermanshah, Iran.


In this paper, the flow in the vicinity of rectangular side orifices placed in main channels is estimated by means of the FLOW-3D model. To reconstruct the flow free surface, the volume of fluid (VOF) approach is utilized. In addition, the standard k-ε and RNG k-ε turbulence models are employed to predict turbulence flow. According to the results obtained from the numerical modeling, the RNG k-ε turbulence model has higher accuracy than the standard k-ε. The analysis of the numerical modeling results proved that this model forecasts the discharge coefficient of side weirs with suitable accuracy. On the other hand, the mean absolute percent error (MAPE) is calculated equal to 12.204%. Also, the maximum pressure is simulated near the main channel bed. Moreover, the minimum pressure is estimated near the flow free surface. Regarding the numerical simulations, the maximum turbulence energy state occurs near the inlet of the side orifice and by increasing the side orifice dimensions the flow field turbulence energy value increases.


Akhbari A., Zaji A.H., Azimi H., Vafaeifard M., Predicting the discharge coefficient of triangular plan form weirs using radian basis function and M5’methods, Journal of Applied Research in Water and Wastewater 4 (2017) 281-289.
Aydin M.C., CFD simulation of free-surface flow over triangular labyrinth side weir, Advances in Engineering Software 45 (2012) 159-166.
Aydin M.C., and Emiroglu M.E., Determination of capacity of labyrinth side weir by CFD, Flow Measurement and Instrumentation 29 (2013) 1-8.
Azimi H., and Shabanlou S., Numerical study of the effect of the bed slope change of circular channel on supercritical flow along the side weir, Water and Soil Science 27 (2017) 53-64.
Azimi H., and Shabanlou S., 3D Simulation of Supercritical Flow Characteristics in Circular Channels with Side Weirs, Water and Soil Science 28 (2018)119-130.
Azimi H., Shabanlou S., Salimi M.S., Free surface and velocity field in a circular channel along the side weir in supercritical flow conditions, Flow Measurement and Instrumentation 38 (2014) 108-115.
Azimi H., Hadad H., Shokati Z., Salimi M.S., Discharge and flow field of the circular channel along the side weir, Canadian Journal of Civil Engineering 42 (2015) 273-280.
Azimi H., and Shabanlou S., The flow pattern in triangular channels along the side weir for subcritical flow regime, Flow Measurement and Instrumentation 46 (2015) 170-178.
Azimi H., Shabanlou S., Ebtehaj I., Bonakdari, H., Discharge coefficient of rectangular side weirs on circular channels, International Journal of Nonlinear Sciences and Numerical Simulation 17 (2016) 391-399.
Azimi H., Shabanlou S., Ebtehaj I., Bonakdari H., Kardar S., Combination of computational fluid dynamics, adaptive neuro-fuzzy inference system, and genetic algorithm for predicting discharge coefficient of rectangular side orifices, Journal of Irrigation and Drainage Engineering 143 (2017) 04017015.
Bazaneh M., Khorsand A., Zeinalzadeh K., Besharat S., Evaluation of HYDRUS 2D software to estimate stored water and wetting pattern of surface drip irrigation, Water and Soil Science 26 (2016) 287-301.
Ebrahimzadeh A., Ziaei A., Jafarzadeh M., Beheshti A., Sheikh Rezazadeh Nikou N., Numerical modeling of one-dimensional flow in furrow irrigation by solving the full hydrodynamics equations using roe approach, Water and Soil Science 28 (2018) 41-51.
Hussein A., Ahmad Z.,Asawa G.L., Discharge characteristics of sharp-crested circular side orifices in open channels, Flow Measurement and Instrumentation 21 (2010) 418-424.
Hussein A., Ahmad Z., Asawa G.L., Flow through sharp-crested rectangular side orifices under free flow condition in open channels, Agricultural Water Management 98 (2011) 1536-1544.
Karizi A., and Honar T., Study of flow pattern and shear stress of broad edge rectangular side weir, Journal of agricultural and natural resources sciences and technology, Soil and water sciences 14 (2008) 15-25.
Oliveto G., Biggiero V., Hager W.H., Bottom outlet for sewers, Journal of Irrigation and Drainage Engineering 123 (1997) 246-252.
Qu J., Three-dimensional turbulence modeling for free surface flows. PhD thesis, Concordia University, Montreal, Quebec, Canada (2005).
Ramamurthy A.S., Udoyara S.T.Serraf S., Rectangular lateral orifices in open channel, Journal of Environmental Engineering 135 (1986) 292-298.
Ramamurthy A.S., Udoyara S.T., Rao M.V.J., Weir orifice units for uniform flow distribution, Journal of Environmental Engineering 113 (1987) 155-166.
Shabanlou S., Yosefvand F., Azimi H., Ebtehaj I., Modeling discharge coefficient of rectangular side orifices, Water and Soil Science, 29 (2019) 83-96.
Tadayon R., Modeling Curvilinear Flows in Hydraulic Structures. PhD thesis, Concordia Unversity, Montreal, Quebec, Canada (2009).
Tarek M., Imran J., Chaudhry H., Numerical modeling of three- dimensional flow field around circular piers, Journal of Hydraulic Engineering 130 (2004) 91-100.