A finite element model of circulation in shallow water with moving boundary on tidal-flat

To examine the circulation in shallow water with tidal flat,a finite element model for the numerical solution of the shallow water equations was developed by means of standard Galerkin's method.The domain computed was covered with triangular finite elements,and water elevation and velocity were approximated by linear interpolation functions,and the lumped coefficients were used to substitute for solving the high order algebraic equation system.The time-dependent land-water boundary changes are treated mathematically by interrelating the location of the land-water boundary with the instantaneous tidal level.The implicit scheme was adopted for the terms of the bottom friction and the Coriolis effect in the motion equation so that the numerical stability of the model has been improved.
The model was applied to the tidal current on shoaling water with large tidal flat off Pikou,and a comparison between observed and calculated values showed good agreement,the flow pattern being reproduced.