NUMERICAL SIMULATION OF SEDIMENT TRANSPORT NEAR SEA BED UNDER WAVES

The sediment transport near sea bed under waves is simulated using a three-dimensional (3D) numerical model that solves Navier-Stokes equations for incompressible flow, the sediment transport equation and the bed morphology equation. The numerical model consists of two basic modules, the 3D hydrodynamic module (HD) and sediment transport module (ST). The sigma-coordinate is used to convert the wavy flow-field into a cube leading to the easier realization of flow-field and boundary conditions. The model is able to simulate the dynamic change of suspended sediment concentration and bed morphology under various flow conditions. The case where the initial flow-field is full of evenly distributed suspended sediment subjected to a linear wave train is simulated. The results on sediment concentration distributions in the horizontal and vertical directions and resulting bed morphology are verified by the analytical solutions developed in this study. The good agreements between the numerical and analytical results show that the present numerical model is reliable in predicting sediment transport in coastal areas under waves.