CFD Online Discussion Forums

CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)
-   OpenFOAM Running, Solving & CFD (https://www.cfd-online.com/Forums/openfoam-solving/)
-   -   solving a set of coupled equation in foam (https://www.cfd-online.com/Forums/openfoam-solving/141723-solving-set-coupled-equation-foam.html)

tjliang September 15, 2014 06:05

solving a set of coupled equation in foam
 
hello everyone,

i am now trying to solve 4 highly coupled equations in chtmultiregionfoam with 4 parameters(ne for electron number density, Te for electron temperature, Th for ion temperature and E for electric field). Those are all one dimensional and hopefully I can ,after calculation, to get the distribution of the 4 parameters along x axis. The 4 equations are highly coupled and need to be solved simultaneously. Has anyone good ideas about how to implement it into cht-solver using C++?

olivierG September 15, 2014 11:30

hello,

I have already done that, but with 1.6-ext version and coupled matrix. So take a look at the now foam extend 3.1, which have block coupled solver.
With cht solver, you will have weak coupling, so very (very) small time step.

Regards,
olivier

tjliang September 15, 2014 15:05

Quote:

Originally Posted by olivierG (Post 510406)
hello,

I have already done that, but with 1.6-ext version and coupled matrix. So take a look at the now foam extend 3.1, which have block coupled solver.
With cht solver, you will have weak coupling, so very (very) small time step.

Regards,
olivier

Thank you oliver, your answer has brought great hope for me. I would be the most greatful of you if you could offer some works of what you have done about that as a tutorial for me.I am really confused of this problem and struggling for it.
If you please , any useful hints or tutorials of yourself available please kindly sent to my email: liangpengtj@hotmail.com. Thanks a lot and best wishes!

Your Peng

tjliang September 16, 2014 05:43

By the way , i am still not sure if in openfoam, two temperatures (one for electron and another foe ions) can be at the same time defined. Are there any comparable models with that of mine? I wish someone could offer me help.Thanks a lot.

olivierG September 19, 2014 04:04

Hello,

You could perfectly have 2 or 3 species temperature, but you need codding here.
I can"t give you my plasma code since it is not free (job work).

regards,
olivier

tjliang November 10, 2014 07:44

Quote:

Originally Posted by olivierG (Post 510900)
Hello,

You could perfectly have 2 or 3 species temperature, but you need codding here.
I can"t give you my plasma code since it is not free (job work).

regards,
olivier

Hello Oliver,

I have done the coding with two different temperature equation and also a set of equations which is also coupled with Te and Th, but every time I change the sequence of my equations I got quite different results( I have totally 12 equations, and I solve them not at the same time but one after another). So I want to ask if I use the coupled Matrix method in my ChtmultiregionFoam , will I get the results a little bit better, I mean my result will not depend on the sequence of the equation system. Can you offer me some suggestions? Thank you.


All times are GMT -4. The time now is 12:19.