CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   OpenFOAM Running, Solving & CFD (http://www.cfd-online.com/Forums/openfoam-solving/)
-   -   Fluent OpenFoam comparison kepsilon model (http://www.cfd-online.com/Forums/openfoam-solving/58086-fluent-openfoam-comparison-kepsilon-model.html)

alimansouri January 15, 2009 12:20

Hi there I Can't match the
 
Hi there

I Can't match the turbulent viscosity between
the Fluent - OpenFoam (used the same mesh),

my model is a 2D turbulent flow, the velocity field is almost the same...but k and epsilon are different,

any idea?

thank you,
Ali.

prashant24983 January 16, 2009 00:21

check your turbulence paramete
 
check your turbulence parameters at the boundaries.... further, I would like you to confirm if your solution has converged?

Your k and epsilon values should be properly initialized to reach convergence quicker. Please refer the user manual for initialization. Once convergence is achieved, results should be independent of the starting conditions.

Goodluck
Prashant

alimansouri January 16, 2009 11:58

Hi Prashant thanks for your
 
Hi Prashant

thanks for your reply, yes my simulation is converged.

However the absolute values of both K and epslion are different from Fluent.

I estimated the initial values of K and epsilon as well...

is there any thing else that might cause the problem ? any other setting in OpenFoam?


Even my velocity field they are not exactly the same... should I get identical results ?


thanks!

markusrehm January 19, 2009 03:19

Hi Ali, last week in one of
 
Hi Ali,

last week in one of my simulations I noticed a limitation of k or epsilon (don't remember). So I changed the tolerance of the equations from 1e-7 to 1e-14 and the k and epsilon field changed considerably. I used realizable-k-eps.

Maybe that helps.

Regards, Markus.

gwierink January 19, 2009 03:57

Hi Ali, A bit lateral to yo
 
Hi Ali,

A bit lateral to your problem here, but perhaps useful for your research interest is that Hannu Ahlstedt presented a poster on k-epsilon comparison between Fluent and OpenFOAM at the 2008 OpenSource CFD conference in Berlin last December. The title is "Comparison of turbulence models in case of three-dimensional diffuser" by Aku Karvinen and Hannu Ahlstedt. On the website of the conference it says the proceedings will be online soon.

Regards, Gijsbert

alimansouri January 19, 2009 10:35

Hi, thanks Markus and Gijsb
 
Hi,

thanks Markus and Gijsbert for your feedbacks,
much appreciated, Ali.


All times are GMT -4. The time now is 20:05.