AN EFFICIENT OPERATOR SPLITTING SCHEME FOR 3-DIMENSIONAL HYDRODYNAMICCOMPUTATIONS

A new efficient numerical method for three-dimensional hydrodynamic co mputations is presented and discussed in this paper. The method is bas ed on the operator splitting method and combined with Eulerian-Lagrang ian method, finite element method and finite difference method. To inc rease the efficiency and stability of the numerical solutions, the ope rator splitting method is employed to partition the momentum equations into three parts, according to physical phenomena. A time step is div ided into three time substeps. In the first substep, advection and Cor iolis force are solved using the explicit Eulerian-Lagrangian method. In the second substep, horizontal diffusion is approximated by implici t FEM in each horizontal layer. In the last substep, the continuity eq uation is solved by implicit FEM, and vertical diffusion and pressure gradient are discretized by implicit FDM in each nodal column. The sta bility analysis shows that this method is unconditionally stable. A nu mber of numerical experiments have been performed. The results simulat ed by the present scheme agree well with analytical solutions and the other documented model results. The method is efficient for 3D shallow water flow computations and fully fits complicated configurations. (C ) 1998 John Wiley & Sons, Ltd.