Three-dimensional numerical simulation for an open channel flow with a constriction

Flow characteristics in an open channel with a constriction are investigated numerically by using a three-dimensional multi-level hydrodynamic model. In this model. the two-step Euler predictor-corrector algorithm is introduced to predict and correct free surface water level. The momentum equations in horizontal directions are discretized in an explicit scheme for the component velocities u and v, and the continuity equation is discretized for the velocity w in an implicit scheme in uniform and non-uniform grid systems. The model has been tested against analytical solutions for two standard cases and used to study sudden contraction and expansion open channel flow. The numerical results are in good agreement with analytical and experimental data. Simulated flow patterns for the sudden contraction and expansion flow show reasonable flow characteristics downstream of an opening.