Laboratory experiments are conducted to measure the velocities of 2D turbulent open channel flow upstream of a vertical sluice gate. The flow case having the same conditions with the experiment is analyzed by computational fluid dynamics simulation. The finite element method is used to solve the governing equations by employing the standard k-epsilon and standard k-omega turbulence closure models. The volume of fluid method is used to determine the free surface of the flow. The numerical results for the velocity field and the free surface profile from eight different computational meshes are compared with the experimental data, and based on the comparisons; the most suitable mesh system among the eight is selected. The comparisons of the numerical and experimental results show that the numerical simulation using the k-epsilon turbulence closure model predicts the velocity field and free surface profile more accurately compared to that of the k-omega turbulence model.