Uncertainty about results of water flow and solute transport (hydrus 2D)

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Uncertainty about results of water flow and solute transport (hydrus 2D)

Post by Ann » Wed Sep 28, 2022 9:22 am

Good morning Prof. Simunek
Thanks a lot for your answer.
I refer to the same model as in the previous question: I want to simulate nitrogen decay chan, hydrostatic conditions are used as initial water condition, and as boundary condition I use seepage face and third-type on the bottom.
I have some doubts about the results, in particular:
- in "boundary water fluxes" results section, nothing is shown as seepage face flux. How is it possible? Does it mean that nothing coming out of the bottom? Everything seems okay for atmospheric flux, root water uptake, surface runoff, evaporation and infiltration
- in "boundary solute fluxes" results section, no results are shown. Why? What is the problem?
- in the graphical results section, advancing the time layer, there is no change in concentration 1 and concentration 2 (whose initial value was numerically set as constant for the whole substrate in initial conditions). In contrast, temporal changes in pressure head, water content and root water uptake are evident

Thank you in advance for your response.

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Re: Uncertainty about results of water flow and solute transport (hydrus 2D)

Post by Jirka » Wed Sep 28, 2022 6:04 pm

No seepage face flux: I would assume that the bottom of the profile remained unsaturated. The seepage face flux occurs, by definition, only once full saturation is reached.

No results for boundary solute fluxes are shown: What do you mean? There is no output or solute fluxes are zero? If former, you likely have the problem incorrectly defined, if latter, you likely do not have any solute fluxes across boundaries.

No changes in concentrations: How should I know why this occurs? You either do not have any concentration changes or you defined the problem incorrectly.


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