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boundedness of the result (negative solute concenteration)

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Old   August 1, 2010, 17:54
Default boundedness of the result (negative solute concenteration)
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Muhammad reza hassani
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Dear foamers
I have added a scalar transport equation to nonNewtonianIcoFoam solver to solve mass transport equation. I expected the results of concentration to be positive all over the domain, however I found out that there are some negative value for the concentration at some points.
anyone have any idea of how I can change the setting of the solver to get more realistic results? may be changes in the interpolation scheme or time marching (implicit or explicit) can be effective?
by the way, the case is the release of a solute at the inlet of an 2D expansion of a tube.
muhammad
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Old   September 2, 2010, 18:18
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Santiago Marquez Damian
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Hi Muhammad. What div and temporal schemes are you using? Try gauss upwind for div and euler for time, both are first order accurate but ever bounded. If you have problems again you have to look at in another place.

Good luck.
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Old   November 30, 2010, 05:30
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Quote:
Originally Posted by mhassani View Post
Dear foamers
I have added a scalar transport equation to nonNewtonianIcoFoam solver to solve mass transport equation. I expected the results of concentration to be positive all over the domain, however I found out that there are some negative value for the concentration at some points.
anyone have any idea of how I can change the setting of the solver to get more realistic results? may be changes in the interpolation scheme or time marching (implicit or explicit) can be effective?
by the way, the case is the release of a solute at the inlet of an 2D expansion of a tube.
muhammad
hi mhassani
i have a problem and i think you can help me.
my problem is mass transfer from solid to liquid with electrochemical method and i want simulate this problem with openfoam and i cant find solver for it.
how resolvent your problem?
use a solver or write a code for it.
if you write a code : can i have your code?
very very thank in advance
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Old   December 2, 2010, 14:29
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Muhammad reza hassani
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Dear Siavash
sorry for late response of mine. I don't know about electrochemical method. the problem of mine involved with a simple convection-diffusion equation. the method of adding the equation was described through a powerpoint tutorials available on internet. it is no difficult. you can find it so easy.
you just create a file with "*.h" extension and include it in the solver code. you have to compile the new solver after modification of the make files.
the boundedness of the concentration still remains unsolved.
regards
hassani
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Old   December 4, 2010, 04:12
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Originally Posted by mhassani View Post
Dear Siavash
sorry for late response of mine. I don't know about electrochemical method. the problem of mine involved with a simple convection-diffusion equation. the method of adding the equation was described through a powerpoint tutorials available on internet. it is no difficult. you can find it so easy.
you just create a file with "*.h" extension and include it in the solver code. you have to compile the new solver after modification of the make files.
the boundedness of the concentration still remains unsolved.
regards
hassani
dear hassani
thanks for your attention
i have prolem same you.
i have mass transport eq in a domain and i want to know:
do you have code for mass transport eq with openfoam?
can you give me your code? maybe i can change it and use it in my case.
very thanks in advance.
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