Experimental and numerical modeling of flow over a trapezoidal broad-crested weir

In this study, the flow properties over a trapezoidal-broad crested weir are investigated experimentally and numerically. The velocity field of the open channel flow over a trapezoidal-broad crested weir is measured by Laser Doppler Anemometry. The governing equations of the fluid motion are solved numerically by ANSYS-Fluent program based on finite volume method. Standart k-?, Renormalization group k-?, Realizable k-?, Modified k-? Shear Stress Transport and RSM turbulence closure models are used in the numerical modeling and the flow profiles are computed using VOF method. The independence of the numerical solutions from the grid structure is tested with GCI (Grid Convergence Index). The numerical results for the velocity field are compared with the experimental results and all of the turbulent closure models are found to be successful in determining velocity field and flow profile. However, in the region of flow affected by the weir structure, RSM model is found slightly more successful than the other turbulence models used in this study. Keywords: Trapezoidal-broad crested weir, LDA, Turbulence models, Finite volume method, VOF