Abstract

This paper reports a numerical simulation in the Amazon water system, aiming to develop a quasi-3D numerical tool for refinedly modeling turbulent flows and passive mass transport phenomena in natural waters. Three depth-averaged two-equation closure turbulence models,  - ,  - , and  - , were used to close the non-simplified quasi three-dimensional hydrodynamic fundamental governing equations. The discretized equations were solved by advanced multi-grid iterative method under non-orthogonal body-fitted coarse and fine grids with collocated variable arrangement. Except for steady flow computation, the processes of contaminant inpouring and plume development at the beginning of discharge, caused by a side-discharge of a tributary, also have been numerically investigated. The used three depth-averaged two-equation closure models are all suitable for modeling strong mixing turbulence. The newly established turbulence model, such as  -  model with higher order of magnitude of transported variable  , provides a possibility to crease the computational precision.

Key words: River modeling, numerical modeling, contaminant transport, depth-averaged turbulence models, multi-grid iterative method.