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Coupling an Underflow Model to a Three-Dimensional Hydrodynamic Model |
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| Authors: | Chris J. Dallimore Ben R. Hodges J?rg Imberger |
| Affiliation: | 1Research assistant, Centre for Water Research, Univ. of Western Australia, Perth 6009, Western Australia. 2Assistant Professor, Environmental and Water Resources Engineering, Dept. of Civil Engineering, Univ. of Texas at Austin, Austin, TX (corresponding author). 3Professor and Chair, Centre for Water Research, Univ. of Western Australia, Perth 6009, Western Australia. |
| Abstract: | A separate underflow model is coupled to the three-dimensional (3D) estuary and lake computer model. The underflow equations are solved on a two-dimensional (2D) grid underlying the 3D model grid. The underflow model entrains ambient water whose properties are given by the fluid properties of the bottom boundary cells in the 3D model. This new approach allows improved representation of underflow effects in z-coordinate models by reducing numerical convective entrainment. An idealized case is used to illustrate the benefits of the underflow model. Comparisons of model results and field data for a saline underflow event in Lake Ogawara and a cold-water underflow in Lake Kinneret demonstrate improved model capability in representing underflow events that are thin compared to the vertical grid scale. |
| Keywords: | Currents Inflow Reservoirs Hydraulic models Two-dimensional models Australia Lakes Three-dimensional models |