Barotropic Flow in the Vicinity of an Idealized Inlet - Simulations With the ADCIRC Model

摘要

The flow in the vicinity of an idealized tidal inlet is studied using the nonlinear finite-element model ADCIRC. The principal aim is to establish a database of results to identify, analyze, and explain the processes in and near tidal inlets of the Mississippi Sound region in the northeast Gulf of Mexico. Coastal waters in the northeast Gulf of Mexico are forced by a combination of tides, river runoff, and wind. The effects of these forcings, and that of advection, Coriolis acceleration, and barrier islands are studied. The two- dimensional (2D) depth-averaged results derived from the three-dimensional (3D) model computations are similar to those computed by the 2D model for the tidally driven flow, whereas they are significantly different for the wind- and river- induced flow. Counter-rotating eddies are produced by tides when convective terms are included in the simulation. Coriolis acceleration accounts for the asymmetry within and outside the inlet. The flow in the region is weakly nonlinear. The wind- and river-induced flows contribute mainly to the residual circulation. Both the magnitude and the direction of the flow change from the surface to the bottom. The presence of the barrier island modifies the direction of the tidally induced flow in the inlet.