Modelling with Reference to the Dispersion Model

The one dimensional dispersion model is used frequently for the evaluation of soil column experiments. Thereby it is supposed implicitly that the tracer concentration distribution measured on the column exit represents the mean value of the cross section (column radius R)  

The effective dispersion coefficient (Dg calculated with the function C (z,t) at z = I (I = column length) is influenced both by axial dispersion ) and radial dispersion (D f  

If the velocity distribution is different in different cross sections the effective dispersion coefficient is not constant but a function of column length z  

The velocity distribution and the function D z) can be calculated from the results of tomographic tracer experiments. On this way a more accurate hydrodynamic modelling and therefore a more exact determination of geochemical parameters is possible. 

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