• medium
• soil
• solute
• transport
• unsaturated

In this thesis I do some simulations about the solute transport in the soil.
The code that I used is provided by Olaf Ippisch (Univer. of Heidelberg)
and it is called muphi. This code is able to compute the dynamics of the
water and the evolution of a solute pulse in a soil, modeled as porous medium,
given the material parameters that define the kind of porous medium, and
the initial condition of both the water and the solute. It also can simulate
heterogeneous structures, with different kind of porous media and geometries.
In the first part of this thesis I summarize the theory of the water flow
and solute transport in porous media.
In the second part I give a very brief description of the code and I intro-
duce the quantities that we consider in the result part, like the moments of
the solute probability distribution, the dilution index and the reactor ratio.
In the third part I show the results of different numerical simulation in
unsaturated media, in order both to check the code and to give an idea of
the behaviour of the quantities I am interested in.
In the last part I finally compare my results with the ones of the ex-
periments performed by Steffen Heberle and Christina Esterle (Univ. of
Heidelberg, Department of environmental physics). To do this, I choose ap-
propriate material properties, and I learn that that the code can very well
predict the mean motion of the solute pulse, but has some problems with
its spreading. In fact the dispersion is, probably, mainly due to the small
scale variability of the water velocity field (that is not yet considered in the
model), and so, in order to fit the spreading evolution of the pulse it should
be inserted in the dispersion coefficient a dependence on the water velocity.