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Old   January 27, 2011, 09:07
Default OpenFoam vs Fluent
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I try to calculate a flow around building. So, I did a mesh in gambit and calculate in Fluent. After this, I load mesh in OpenFoam and try to calculate in it. I use the same boundary condition, but every time i have very big value of time step continuity error, epsilon and k.
I use a k-epsilon model in SimpleFoam.
Why Fluent calculate my problem, and OpenFoam can't?
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Old   January 27, 2011, 10:58
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Is it a 2D model?

Can you use checkMesh in OpenFoam to see the detail of the mesh?

Maybe you've got some undefined faces...
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Old   January 27, 2011, 11:01
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Quote:
Originally Posted by cheng1988sjtu View Post
Is it a 2D model?

Can you use checkMesh in OpenFoam to see the detail of the mesh?

Maybe you've got some undefined faces...
My Mesh is 3D. I always use checkMesh after import it from another application. Mesh is OK
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Old   January 28, 2011, 04:47
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please check for the internal fields in ~/0/epsilon,k,u and of cource for the bc.values (garbage in , garbage out... )

i think you just started with unphysical internal values. no offense, but as often is i blew up a solver run as often it was my fault because of bad initialization and fancy bc.

try to do a potentialFoam on beforehand to get an initial guess.

neewbie
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Old   January 28, 2011, 04:51
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Could you please elaborate a little more on your problem.....with regards to the schemes you used in OpenFoam and also the solvers used...



Regards,

Amol
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Old   January 31, 2011, 09:15
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today I try to use a Spalar-Allmaras model, because k-eps was converged only with vary small relaxation factors.

When I look velocity, I see, that in magnitude I have only positive values, in axes y and z-positive and negative. But in X-only positive, so as I understand I haven't a vortex.
But fluent shows a lot of vortexes.

Where mistake?
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Old   February 1, 2011, 02:30
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Hello,

before we can try to answer you should give us a bit more information :-)

- What solver are you using?
- Post your fvSchemes and your fvSolution dictionaries
- Post the output of checkMesh
- Describe the setup of your boundary conditions

Typically if you are forced to use very small relaxation factors, it means there is something wrong in the case setup (I would say most probably BC's).

Best,
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Old   February 2, 2011, 08:39
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Hello,

I use case simpleFoam
My fvSchemes and fvSolution

Also, output of checkMesh-in log file

And boundary Conditions are in 0.zip
Attached Files
File Type: txt fvSchemes.txt (1.8 KB, 24 views)
File Type: txt fvSolution.txt (1.9 KB, 18 views)
File Type: txt log.txt (2.8 KB, 14 views)
File Type: zip 0.zip (20.5 KB, 18 views)
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