• Re: Gravity term effect on transport over a long period

Thinking again about it, I guess that the answer is rather simple. The hydraulic-head has to take into account the height difference and consequently the gravity term...

• Gravity term effect on transport over a long period

Dear,

I want to model a 2D "diffusion driven" process in a homogeneous medium (pressure gradient=0, gravity along negative y). Qualitatively the solute is "simply" spreading over the whole domain. The hydraulic conductivity is rather low about 1e-10 m/s.

However, over a very long period, let's say 100 000 years (3.16E12 s), according to the generalized Darcy's law (see for example: https://en.wikipedia.org/wiki/Darcy%27s_law), I would expect the plume to move in the direction of the gravity because of the gravity term in the Darcy's law.

In practice I do not observe this phenomena in the FEFLOW results. Is my interpretation incorrect or did I miss to specify something in FEFLOW?

Best regards,
• Re: How to access the different masses in multispecies problem

If it can be useful to other people, here is the answer:

If you need to get information from multiple species, you need first to initialize the species ID and then ask for the result of the mass transport. I have written below the conceptual idea how the plug-in needs to be programmed.

# Set value for first ID

IfmSetMultiSpeciesId

# Get all the values via a loop – specie 1

IfmGetResultsTransportMassValue

# Set value for second ID

IfmSetMultiSpeciesId

# Get all the values via a loop – specie 2

IfmGetResultsTransportMassValue
• How to access the different masses in multispecies problem

Dear,

In a two species problem I would like to access the mass#1 and mass#2 values at a specific node through a a function like

[code]IfmGetResultsTransportMassValue (IfmHandle, int);[/code]

May you please tell me how to proceed?

I am using FEFLOW 7.0.

Best regards,

Olivier
• Re: Reset &quot;sorbed mass&quot; for all elements each time Kappa is changed

I have made a few tries but I did not manage to solve my problem yet.

I start at the very first step with Kappa=0 in the whole domain (all elements) and I check that the computed Sorbed Mass is zero. Then I set a value of Kappa and immediately after (I deal with the same time step) I compute again the Sorbed Mass and I found a positive value.

What I need, I guess, is a way to bypass the "automatic setting" of Sorbed Mass when [i]IfmSetMatMassSorptionCoeff1/2[/i] is called from my plug-in.

Best regards,

Olivier
• Reset &quot;sorbed mass&quot; for all elements each time Kappa is changed

Dear,

I would like to model a relatively classic 2D flow and mass transport problem over a rectangular domain and I need to change the Henri constant Kappa over time.

The problem is that each time Kappa is changed and in addition at the first time step of the simulation, an equilibrium is computed by FEFLOW and then sorbed mass is created resulting in an improper "global" mass balance. Actually, FEFLOW creates sorbed mass by multiplying the dissolved mass by the Kappa coefficient. In order to skirt this behavior I would like to reset created sorbed mass to zero after FEFLOW has created it. This may require retaining previous sorbed value for all elements and reset the new sorbed mass values with those retained values ...

I found inspiration from this post [url=http://forum.mikebydhi.com/index.php/topic,1312.0.html]http://forum.mikebydhi.com/index.php/topic,1312.0.html[/url], but because I am a very new beginner in programming plug-in for FEFLOW I really need basic help to start. Actually, I don't know how to find [i]Ifm[b]Set[/b]ElementalContent[/i] (and not [i]Ifm[b]Get[/b]ElementalContent[/i]) methods to change the sorbed mass.

I have installed Visual C++ 2008 and I chose the following [i]OnTimeStepConstraint[/i] callback (since I know when the change in Kappa occurs).

I have noticed that [i]IfmSORBED_MASS[/i] from [i]IfmContentType[/i] was certainly the parameter I have to deal with through a [i]IfmSetElementalContent[/i] but I didn't find such a method in "document.h".

Can you please give me support for getting started?

Is that better to check whether a change in Kappa has occurred instead of using the [i]OnTimeStepConstraint[/i]?

Best regards,

Olivier