Numerical modeling of flow over an Ogee spillway and investigation of effect of downstream influences on discharge

The main aim of this study was to investigate flow over an ogee spillway and
simulating by numerical model. A commercially available computational fluid
dynamics (CFD) program, which solves the Reynolds-averaged Navier-Stokes
equations (RANS), was used to model the physical model setup. Flow over an ogee
spillway has free surface and turbulent flow so that in some cases calculating flow
rate and flow depths are difficult. Increasing in water level at downstream may
cause reduce in discharge because of suction forces and negative pressure. In this
study, different numerical turbulence models are used to predict discharge and
compared with experimental results. In experiments, discharge and flow depths of
physical model were recorded for 22 different total head over the crest. The results
show that there is reasonably good agreement between the physical and numerical
models for discharges.