A Saltwater Intrusion Model Based on Semi implicit Eulerian-Lagrangian Finite volume Method

Abstract:

A 2D numerical model to simulate tidal flow and salinity in complex estuaries is developed. The grid module is designed under unstructured triangular grid with second order accuracy by cell reconstruction using multiple least square methods to remove stability limitations associated with surface gravity wave. The circulation module is based on semi implicit Eulerian Lagrangian method and free from CFL condition constraint, and the wetting and drying are addressed by movable boundary techniques. The salinity module is designed in the frame work of finite volume method with a second order resolution in coordination with the discreted continuity equation, through the cell face concentration reconstructed from surrounding cell averaged by complex interpolation combined with a mono tonicity criterion. The model has been tested by a pure advection case and a pure diffusion case, which demonstrates that the model has a high accuracy. Finally, this model has been applied to simulating the saline intrusion in the Yangtze (Changjiang)River Estuary and the results show that the simulated tidal levels, velocities and salinities agree well with the measured ones.