CFD Modeling of Varied Flow Conditions Over an Ogee-Weir

Accurate estimation of discharge capacity and local hydrodynamics are essential when designing hydraulic structures. Instead of the application of conventionally used empirical relationships, this study introduces a 3D numerical modeling technique which is capable to adequately predict both the discharge-upstream water level relationship and the flow field around weirs. The numerical model, REEF3D, is validated for different hydrodynamic conditions (free-flow and submerged flow) against laboratory data performed for an ogee type weir. Simulated water surface elevations compared with experimental data together with the modeled flow field around the weir suggest that even the complex modular, transition and non-modular submerged cases can be reproduced by the numerical tool. The study proves that the herein applied numerical solver can be a good alternative of laboratory models for flow analysis at complex hydrodynamic conditions, especially where spatially strongly varying free surface characterizes the flow.