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-   -   boundedness of the result (negative solute concenteration) (http://www.cfd-online.com/Forums/openfoam-programming-development/78759-boundedness-result-negative-solute-concenteration.html)

mhassani August 1, 2010 17:54

boundedness of the result (negative solute concenteration)
 
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

santiagomarquezd September 2, 2010 18:18

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.

siavash_abadeh November 30, 2010 05:30

hi
 
Quote:

Originally Posted by mhassani (Post 269723)
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

mhassani December 2, 2010 14:29

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

siavash_abadeh December 4, 2010 04:12

Quote:

Originally Posted by mhassani (Post 285768)
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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