A process-based model for sediment transport under various wave and current conditions

The purpose of this study is to investigate the capability of a newly developed process-based model for sediment transport under a wide variety of wave and current conditions. The model is based on the first-order boundary layer equation and the sediment advection-diffusion equation. In particular, a modified low Reynolds number k-ɛ model is coupled to provide the turbulence closure. Detailed model verifications have been performed by simulating a number of laboratory experiments, covering a considerable range of hydrodynamic conditions such as sinusoidal waves, asymmetric waves and wave-current interactions. The model provides satisfactory numerical results which agree well with the measured results, including the time-averaged/dependent sediment concentration profiles and sediment flux profiles, as well as the time series of concentration at given elevations. The observed influences of wave orbital velocity amplitude, wave period and sediment grain size are correctly reproduced, indicating that the fundamental physical mechanisms of those processes are properly represented in the model. It is revealed that the present model is capable of predicting sediment transport under a wide range of wave and current conditions, and can be used to further study the morphodynamic processes in real coastal regions.