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3Dmixer on simpleFoam and MRFInterFoam.

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Old   May 6, 2013, 23:15
Default 3Dmixer on simpleFoam and MRFInterFoam.
  #1
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Dongyue Li
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Hi FOAMERS,

I am simulating a 3dMixer just as the uploaded image depicted.Generally I wish I can use simpleFoam or MRFInterFoam to initialize the field then run the interDyMFoam.As we know ,simpleFoam is faster than MRFInterFoam.The best way is using simpleFoam to initialize fields,then interDyMFoam.But now I am facing the problem is simpleFoam's velocity is different with MRFInterFoam.

Look at the image.MRFInterFoam's velocity is in normal direction. the velocity glyph near the shaft is point to the up, and the glyph aside is point to the bottom.
But in simpleFoam the velocity glyph near the shaft does not point to the up.looks like it was imposed some kindy force.and can not move upward..


I am sure its induced by the B.C. this two cases use the same mesh.In simpleFoam,I tried some different combinations.such as:

1.
p outlet: fixedvalue 0;
u outlet:zerogradient;
2.
p outlet: fixedvalue 0;
u outlet:slip;
3.
p outlet: fixedvalue 0;
u outlet:inletOutlet; inletValue (0 0 0);
4.
p outlet: fixedvalue 0;
u outletressureinletOutlet;
5.
p outlet: zerogradient;
u outlet:zerogradient;
(In this B.C. it always said can not satisfy the continuty,I have to run potentialFoam.But after running potentialFoam,it does not work)

In the above 5 B.C. All of them can not make the velocity glyph point to the up.

Now I dont know what to do,does anyone know how to set B.C. in a freeoutlet 3Dmixer in FOAM?

Any comments would be appreciated.

Thanks in advance.
Attached Images
File Type: jpg 1.jpg (56.0 KB, 17 views)
File Type: jpg 2.jpg (74.6 KB, 16 views)
File Type: jpg 3.jpg (54.6 KB, 13 views)
File Type: jpg 4.jpg (66.9 KB, 19 views)
File Type: jpg simplefoam.jpg (56.9 KB, 16 views)
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Old   May 12, 2013, 01:04
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  #2
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Dongyue Li
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I figure this out.I should set p to zerogradient in outlet patch.Otherwise it can squeeze the liquid into the mixer.
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