Numerical Comparison of Three- and Two-dimensional Model for Modeling Meandering Channel Flow

Flow passing through channel bends is three-dimensional. Some three-dimensional models have been developed to simulate this flow phenomenon. However, for practical engineering problems three-dimensional models generally are not computationally efficient, two-dimensional models are thus generally adopted. Previous studies showed that the inclusion of dispersion terms results in improved predictions of vertically-averaged velocity in bend-flow simulations. However, these previous studies did not clarify that to what extent and why the simulated results from the conventional two-dimensional model deviate from the reality in curved channels or to what extent and why the dispersion terms could not be ignored in curved channel flow modeling. In this study, numerical comparisons of vertically-averaged flow results in a U-shaped experimental flume by using two-dimensional model CCHE2D and three-dimensional model CCHE3D, were conducted. Dispersion terms and their intermediate terms were computed using simulated results from the three-dimensional model, which can partly explain the difference of vertically-averaged velocities obtained between two-and three-dimensional models.