Three-Dimensional, Lagrangian Residual Transport Computed from an Intratidal Hydrodynamic Model.

摘要

A procedure was developed for computing three-dimensional, Lagrangian residual circulation from an intratidal hydrodynamic model for driving an intertidal transport model. A three-dimensional, finite difference, hydrodynamic model, CH3D, which uses boundary-fitted coordinates in planform and vertical cartesian coordinates, was indirectly coupled to a water quality transport model that uses an integrated compartment solution. The coupling was accomplished through development of an interface processor implemented within the hydrodynamic model. The processor converts nondimensional, contravariant velocities in transformed coordinates to dimensional, physical flows for the transport model. The sum of Eulerian residual velocities and Stokes' drift was used as a first-order approximation for the Lagrangian residual currents. Stokes' drift approximates residual currents induced by nonlinear interactions of tidal currents and represents the net drift experienced by a particle passing through a spatially varying velocity field in an oscillating flow. A Stokes' drift formulation that guarantees mass conservation was implemented within the interface processor so that intertidal hydrodynamic information could be processed and output as the intratidal hydrodynamic model is executing. This information is used to drive intertidal mass transport. (mm)