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Initial concentration at the node, 1D, Solute transport, Porous media

Posted 18.02.2014, 11:18 GMT-5 Porous Media Flow, Chemical Reaction Engineering, Geometry, Mesh, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 4.3a, Version 4.3b 2 Replies

Antoine Armandine Les Landes
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Hello,

I have a pretty easy 1D model, governed by the solute transport equation. My idea is to coupled it with the geochemical software phreeqc. So I would like to treat the nodes of comsol as phreeqc cells.

So geometrically, it is mainly an interval, from L0 to Ln. I have subdivided the interval into small intervals placing point where a mesh point correspont.

Now I would like to give at each node point a different initial value.
Is it that possible? Or I just can choose a Domain, namely 2 nodes.

I have tried to give values at the nodes points using an initial value node and stating "Initial_Value*(x==Node_point)" where Initial_Value is the value of the concentration and Node_point is a point in the interval [L0, Ln]. Anyway it seems that Comsol makes the average between the neighbors and ignore my value.

I have tried different things but so far there is not a result that please me. I hope it is understandable.

Thank you
2 Replies Last Post 20.02.2014, 04:13 GMT-5
Suresh Seetharam
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Posted: 1 decade ago 19.02.2014, 04:35 GMT-5
Hi,


Use function>interpolation>table (or file if you want to import)

In the first column feed your x-coordinates and in the second column your initial values.

From the above you should get correct nodal values, however, only elemental average in between the two nodes. If you don't like the elemental average then define more intermediate points in your interpolation table to get what you want.

Is this what you are looking for?


Suresh
Hi, Use function>interpolation>table (or file if you want to import) In the first column feed your x-coordinates and in the second column your initial values. From the above you should get correct nodal values, however, only elemental average in between the two nodes. If you don't like the elemental average then define more intermediate points in your interpolation table to get what you want. Is this what you are looking for? Suresh
Antoine Armandine Les Landes
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Posted: 1 decade ago 20.02.2014, 04:13 GMT-5
Thank you.

Yes, well, more or less, I did not tought, or better said, I did not know about the function table option, which helps a lot. But now I wonder about the element average between nodes, I though about creating more points between the nodes that I want to study, but now I wonder if it is possible to remove.
Thank you. Yes, well, more or less, I did not tought, or better said, I did not know about the function table option, which helps a lot. But now I wonder about the element average between nodes, I though about creating more points between the nodes that I want to study, but now I wonder if it is possible to remove.

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