Note on a 2DH finite element model of tidal flow of the North Passage of the partially-mixed Changjiang River estuary, China

A two-dimensional horizontal (2DH) numerical model of flow is established by applying the Galerkin finite element method (FEM). The software EasyMesh is used to triangulate the modeled planar domain. The two-step Lax-Wendroff scheme is used for integrating the equations in order to avoid the nonlinear iterative calculation. The model is validated through numerical experiments on flow in an idealized rectangular flume. The model is then used to study tidal flow within the North Passage of the partially-mixed Changjiang River estuary. The dry-wet method is adopted to deal with the moving boundary hydrodynamic problem. Comparisons are made between modeled and measured hydrographic data for two stations. Modeled results are shown to be in reasonable agreement with measured ones. Horizontal distributions of modeled tidal flow velocity vectors within the North Passage are obtained during the maximum flood tide, the high slack water, the maximum ebb tide, and the low slack water, respectively. This two-dimensional horizontal finite element model was found to be well suited to the complexities of the North Passage of the partially-mixed Changjiang River estuary.