3D layered-integrated modelling of mass exchange in semi-enclosed water bodies

摘要

The flow patterns in semi-enclosed water bodies are generally complicated and have significant effect on the water quality and fluid exchange there. The exchange of of fluid between the semi-enclosed water body and outside is due to two physical mechanisms. The first is the flushing due to tidal effect. The second is the shear induced by the velocity difference between the flow within the water body and outside. To predict the flow and solute transport in these water bodies a three-dimensional layer-integrated numerical model has been developed. To account for the turbulence which consists of the free shear component and the bottom friction component the k-e model is employed. The numerical model has been applied to the cases of tidal flow as well as steady river flow outside a rectangular harbour with or without breakwater. Compared with the available experimental results, the gross mass exchange both due to tidal effect and shear can be estimated satisfactorily by the numerical model.