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Symmetrical Model With Non Symmetrical Solution

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Old   November 7, 2007, 08:07
Default Dragos, you were totally righ
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Luca Liberti
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Dragos,
you were totally right: the flow past a sudden expansion is inherently unstable and asymmetrical
when Re exceeds a critical value. Even the RANS mean flow shows asymmetrical features at least for averaging times used in literature.
See De Zilwa et al. "Flows through plane sudden-expansion" Int. J. for numerical methods in Fluids 2000 32 313-329
As for Jason problem, I guess might help to make the geometry of the join between the main pipe and the smaller ones as gradual and smooth as possible maybe reducing its angle.
Hope it helps
Luca
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Old   November 7, 2007, 11:57
Default Hi Luca, Thank you very much
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Dragos
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Hi Luca,
Thank you very much for the references, I'll try to get them.
Jason, as I remember, the asymmetry appears only for certain ratios between the inlet diameter and expansion diameter. In my oppinion, one of the solutions (besides that suggested already by Luca), you should increase this ratio (decrease the inlet diameter or increase the expansion diameter). It sould be easy to see that with the simple example from above. Just play with the diameters until you get the symmetric solution.
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Old   November 8, 2007, 07:05
Default Hi, Thank you for your comm
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Jason Dale
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Hi,

Thank you for your comments and help. I don't want to take up any more of your time so I will carry on looking into this further and let you know if I manage to solve it.

Kind Regards

Jason
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Old   December 10, 2007, 05:19
Default Hello all would you please
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Armin Hosseinian
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Hello all

would you please any one let me know how can i push flow into the pipe in openfoam?
I have created the geometry of the pipe and also the mesh.
I need to see the velocity profile which comes from the moving flow into the pipe.
I am new user of openfoam and i dont know how can i put the amounts for the u velocity and see the motion of the fluid inside the pipe.

I would appreciate any comments.

sorry if it is not an advance question.

Cheers
Armin
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Old   December 10, 2007, 07:21
Default Hello Armin, I think it would
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Dragos
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Hello Armin,
I think it would be helpfulf for you if you download the case files mentioned above ( POST17811), and start from there.

Dragos
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Old   December 18, 2007, 03:49
Default Dear Dragos Appreciate abot
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Armin Hosseinian
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Dear Dragos

Appreciate abot the answer.
I will work for it.
SOrry i bother you.

Many Thanks again.

Kinds Regards
Armin Hosseinian
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