(423a) Software for Modeling Multiple Emissions in a River

This work presents software based on a three-dimensional model for the dispersion of effluents in rivers using CFD techniques. Several models can be found in the literature, some of which even analyze complex flows. The main contribution of this work is that it proposes a three-dimensional model capable of predicting the dispersion of effluents in very large open channels using Computational Fluid Dynamics. The model is very fast, an unusual feature of CFD models. Due to this, it is possible to predict the dispersion of substances in long sections of rivers with some kilometers in extension. This allows the model to be used as a predictive tool to analyze and guide management decisions of future industrial installations near rivers.

Velocity and concentration profiles are estimated through the numerical solution of the discrete form of the mass, momentum and species conservation equations. If necessary, the developed model can consider the presence of multiple effluents discharges along the river. This flexibility allows for the simulation multiple discharges points in different locations of the river bank. Results for the dispersion of an inert emission in a river near Campinas have been used to validate the model.

The model is very fast. A thousand meters of a river of width of 10 meters and depth of 3 meters takes only about twenty minutes of CPU time on a Pentium IV. The river is discretized in 44,100,000 control volumes. A commercial package would take several days to run a similar problem.

This software can be used on the environment Windows 98/NT/2000. It was developed using three programs that interacts with each other: the mathematical model is programmed in Visual Fortran, the programs interface is in Visual Basic .NET and the graphical results are given by Mat Lab outputs.

The software works as the following: it receives input data that is configured by user, manipulates the data and return to the user numerical and graphical outputs. Inputs: river dimensions, number of effluents, river and effluents velocities, river and effluents concentration of substances, etc. Outputs: concentrations and velocities of the effluents along the 3D river directions.