[amin144]

Dear Foamers,
I have read every posts about pressure driven flow but finally I need some one only tell me is it right my conclusion about pressure boundary condition in poiseuille flow, or not:

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]

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]

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

[nimasam]

yep it seems right

[amin144]

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

[nimasam]

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]

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]

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]

Thanks very much Dear Nima