Description |
CFITIM is a program for estimation of equilibrium and non-equilibrium solute transport parameters from miscible displacement experiments in a steady-state, uniform flow field using a pulse-type or continuous source. Depending upon the exact form of the transport, the program allows up to five different parameters to be estimated. Traditionally, a two-parameter partial differential equation has been used to describe the 1D convective-dispersive transport of chemicals in soils. The parameters in this equation include the dispersion coefficient and a distribution coefficient, the latter accounting for interactions between the chemical and the solid phase of the soil. For linear equilibrium adsorption the resulting model is relatively easy to use. To more adequately simulate the effects observed in experiments, more complex conceptual models need to be used. These models are all based on the assumption that, either for physical or chemical reasons, adsorption does not proceed at an equal rate in all parts of the soil medium. The resulting transport equations contain several parameters which must be quantified before actual predictions can be made in the field. Estimates for these parameters can be obtained by analysing effluent curves from column displacement experiments using least squares. Depending upon the exact form of the transport model, the program allows up to five different parameters to be estimated simultaneously. The program does not have a pre-processor. Input is developed by copying an example data set and creating the new input file with a text editor. The program produces text output files with the results in tabular format. |