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difference between inletValue and value in inletOutlet B.C.

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Old   May 29, 2011, 07:34
Default difference between inletValue and value in inletOutlet B.C.
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Dear foamers
I try to run a case and have a problem with inletOutlet Boundary condition.
What is the difference between the inletValue and value in this B.C.?
It seems that they have a same value in most of the cases.

regards,
Moha
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Old   May 29, 2011, 10:31
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inletOutlet is a back flow boundary condition for outlet. If fluid attepts to flow inwards, it applies a fixed value velocity assigned by inletValue for that given patch face. Or, it use zerogradient.

InletValue is the value flow inwards you have to give.
value is the actual value for the given patch. given by inletValue or patchface neighbour cell(zerogradient).

Hope this helps.

regards, Junwei
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Old   May 29, 2011, 22:43
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Thanks for your answer. It was useful for me.
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Old   May 30, 2011, 13:28
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Junwei, your explanation about inletValue is clear for me but the one for value isn't.

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Originally Posted by su_junwei View Post
InletValue is the value flow inwards you have to give.
value is the actual value for the given patch. given by inletValue or patchface neighbour cell(zerogradient).
Suppose you want a velocity pointing only outwards. It would be zeroGradient if velocity is outwards and (0 0 0) if it is inwards. I suppose inletValue should be (0 0 0) and it would represent the inlet velocity. Then what is the purpose of the "value" entry?.

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Old   May 30, 2011, 21:01
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value is a keyword for all the numerical boundary condition. It is not used for input but calculated based on the boundary you set. It is useful for postprocessing. you can set the same value as inletValue, and it will be updated during the calculation.

sometimes, paraview don't like boundary condition without "value" entry.

Regards, Junwei
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Old   May 30, 2011, 21:42
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Junwei, thanks for the clarification and confirmation. Tthat's true when values are calculated "value" entry data is replaced by which is calculated at running time.

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