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-   -   Yes-No question about poiseuille flow (http://www.cfd-online.com/Forums/openfoam/95709-yes-no-question-about-poiseuille-flow.html)

amin144 December 29, 2011 12:42

Yes-No question about poiseuille flow
 
Dear Foamers, :)
I have read every posts about pressure driven flow :o but finally I need some one only tell me is it right my conclusion about pressure boundary condition in poiseuille flow, or not: :confused:

if we have a pressure driven flow and we don't know about velocity but we know pressure boundary condition,

we use velocity (U/0) in this form:
inlet :
type pressureInletVelocity
value uniform(0 0 0 ) ;
outlet:
type zerogradient

and pressure as below:

inlet:
type fixedValue;
value uniform 1; (we assume 1 is value of pressure at inlet)

outlet
type fixedValue;
value uniform 0;

And another queation, is this pressure value, real or divided by density?:(

nimasam December 29, 2011 13:15

hi dear Amin
please look at the dimension of your pressure file! in 0 folder then you will find whether it is real pressure or divided by rho!

amin144 December 29, 2011 13:37

Dear Nmia
Thanks very much dadash :)
Is the boundary conditions right?

nimasam December 29, 2011 14:30

yep it seems right

amin144 December 29, 2011 15:33

Fan boundary Condition
 
I've heard about some boundary condition which name is FAN ,
any body know different between fan and pressureInletVelocity?:confused:
Is it possible to use it in poiseulle flow?

nimasam January 1, 2012 06:38

fan is periodic boundary condition with a pressure difference between to cyclic face,
i suggest you to look at channelIcoFoam, if you want to cyclic boundary condition, however you can use Fan for pressure driven flow!

amin144 January 2, 2012 13:31

Thanks Dear Nima,
have you any idea about it that how can I understand what OpenFoam Code do, when we use one of any boundary conditions?

nimasam January 2, 2012 14:24

1) there is a little description about each code in .C files, you can look at it
2) search in forum about solver
3) look at OpenWiki
4)chalmarse university maybe you find some extra tutorials

amin144 January 10, 2012 07:10

Thanks very much Dear Nima


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