REVIEW OF RECENT DEVELOPMENTS IN TIDAL HYDRODYNAMIC MODELING .2. TURBULENCE ENERGY MODELS

The second part of this review deals with three-dimensional tidal mode ls for homogeneous and stratified sea regions in which the vertical ed dy viscosity and diffusivity are computed from turbulence energy submo dels. The formulation of a range of turbulence energy models is presen ted, and the solution of the three-dimensional equations using finite difference methods in the vertical on a number of transformed grid (lo g, loglinear) is described. The application of turbulence energy model s is illustrated using results from a three-dimensional model of tides in the Irish Sea. A comparison of computed tidal current profiles det ermined using a two-equation turbulence closure model with those deriv ed using a simple flow-dependent eddy viscosity model, and with observ ations, did not reveal any significant differences between the models. Recent work on the effect of stable stratification on turbulence ener gy and tidal currents is also considered, as this is the more critical test of the accuracy of turbulence energy models. Processes influenci ng the internal tide generation in regions of steep topography are als o examined using the three-dimensional turbulence energy model with a prognostic density field. The role of the nonlinear terms in the gener ation of short internal waves at the top of the shelf break, and inten se surface and bed mixing in this region is examined together with the effects of an upwelling and downwelling favorable wind.