Moving Boundary Technique In ECOMSED And Its Application

The ECOMSED is widely used in simulating offshore current which adopts Sigma coordinate system. However the ECOMSED is not suitable for simulating current in tidal flat because of lacking of a suitable moving boundary technique in the model.In this thesis, a drying-wetting moving boundary technique is applied into the model and tested on a 2D uniform slope and a 2D circular shoal. The simulation results agree well with the the previous research, the water surface line is smooth, and neither zero water depth nor negative water depth appears.The improved ECOMSED hydrodynamic model is applied to the tidal current simulation of Nanpai River fishery port. The results indicate that the calculated water level and velocity agree with the data in site, so the discrete method, the boundary condition and parameters determined in the model are reasonable. Then, a wave model and a sediment model are coupled into this hydrodynamic model to separately simulate the sediment transport with the pure tidal current and with wave-current coexisting. The results of this two models can both describle the principle of the sediment transport, but the result of the latter model is better than the one of the former. It shows that ignoring the wave effect when simulating the near shore area where the tide effect is dominant is feasible. However, if the conditions permitting, it is advisable to consider the impact of the wave. This research extends the capability of ECOMSED to simulate the near shore area.