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-   -   Boundary Condition (http://www.cfd-online.com/Forums/openfoam-solving/60045-boundary-condition.html)

vatant April 15, 2005 10:59

Hello, I tried to use "pres
 
Hello,
I tried to use "pressureTransmissive" boundary condition with lInf specified. however, when i ran my code : it said ,

FOAM FATAL IO ERROR : keyword lInf is undefined in dictionary "/run/tutorials/../0/p:: Outlet"

..
Function:dictionary :: lookupEntry (const word& keyword) const
in file : db/dicitonary/dictionary.C at line : 148

I dont know how to fix this. Should i include any extra lib files in /make/options ?


Thanks


Vatant

henry April 15, 2005 11:14

It sounds like you have made a
 
It sounds like you have made a mistake in way you have added the lInf entry.

vatant April 15, 2005 11:39

In the /case/0/p file bound
 
In the /case/0/p file

boundaryField
{
Outlet
{
type pressureTransmissive;
pInf 1e5;
lInf 0.5;
}
.
.
}

etc

I did not use pressureTransmissive type patch in the mesh i imported frm fluent.

Do you think, I need to add the pressure type patch anywhere else ?

Thanks

Vatant

vatant April 15, 2005 14:52

Dr.Weller, I tried to u
 
Dr.Weller,

I tried to use zeroGradient for velocity at outlet and this error disappeared. However, I have an compressible flow scenario and hence my rho field reads:

{
Inlet
(
type inletOutlet;
inletValue 920;
)
Outlet
(
type inletOutlet;
inletValue 900;
)
.
.
.
.
}

I tried using this condition using OpenFoam 1.0 and Foam Exited.

I am not sure how to handle the pressuretransmissive nature using Foam...

in my case, i have an totalpressure in a tank with an exit nozzle where pressuretransmissive is required due to reflective boundary nature.

( a compressible laminar liquid flow)


My velocity at inlet is 'pressureinletoutletvelocity' calculated using the total pressure ..and at outlet ..i guess..zerogradient is appropriate due to pressuretransmissive nature.

the domain is initially with water everywhere..and hence i used,

{
inlet
(
type inletOutlet;
inletValue ...
)
...
...

and at the Outlet..i tried different combinations

)

I had earlier run with constant pressure outlet (fixed value) but the solution easily showed boundary reflection.

Could you help me handle the boundary conditions ?

Thanks


Vatant

henry April 15, 2005 17:38

The pressureTransmissive press
 
The pressureTransmissive pressure BC is currently written for gases not liquids, if you need a version for liquids you will have to write a version for yourself based on the one I wrote for gases.

vatant April 15, 2005 18:20

Thanks Dr.Weller. Where can i
 
Thanks Dr.Weller. Where can i find pressureTransmissive BC module for gases so that I can try and set one up for liquids.


Vatant

henry April 17, 2005 07:20

You will find the source code
 
You will find the source code for all the physical boundary conditions in OpenFOAM-1.1/src/OpenFOAM/fields/fvPatchFields/derivedFvPatchFields

vatant April 18, 2005 09:30

How can i include the required
 
How can i include the required boundary conditions patch fields to my /username/applications ?

I have the required p0, rho0,psi for calculation in pressureTransmissive ..does it require any other parameter ? I guess the p0 is the boundary outlet pressure itself ..with rho0 = rho(t=0) given.

With these where should i place my fields file *.C and *.H for my application ?

Thanks


VATANT

vatant April 19, 2005 19:06

Dr.Weller, I modified onl
 
Dr.Weller,

I modified only the p0, rho0 and PSI for pressureTransmissive to read. Does this condition work differently for gas and liquids or can i jus use different p0, rho0 and PSI (for liquids) ?

In the pressureTransmissive conditions, wht if lInf = 0 does it imply completely non-reflective conditions ( I guess this is Navier Stokes Characteristic Boundary Condition NSCBC's)

Also, If my actual boundary value (pressure exit ) is say Pexit, does Pinf in pressureTransmissive same as Pexit ? (if it was a fixedValue pressureOutlet) ?


Thanks


Vatant

olivier September 19, 2005 15:58

I patch a value of a field in
 
I patch a value of a field in a wall boundary at each iteration.
what is the type which I should associate to this boundary, knowing that zeroGradient generate a false segmentation after the 4th iteration.
thanks a lot

olivier September 20, 2005 12:49

can some one help me please th
 
can some one help me please thank you
I patch a value of a field in a wall boundary at each iteration.
what is the type which I should associate to this boundary, knowing that zeroGradient generate a false segmentation after the 4th iteration.

eugene September 20, 2005 13:10

I dont understand what you mea
 
I dont understand what you mean. If you are altering the boundary value, it clearly cant be zeroGradient. What are you doing and why are you doing it?

olivier September 20, 2005 17:36

Hi Eugene I have two zones of
 
Hi Eugene
I have two zones of calculation, over these zones I resolve different equations.

potential vector values obtained in the inferior wall (buttom) of the 1st zone must be patched in the walls superior wall (top) of the 2nd zone.

what is the type which I should associate to this boundary (superior and inferior wall).
thanks a lot

mattijs September 21, 2005 04:06

I guess something like bott
 
I guess something like

bottom: zerogradient (i.e. extrapolated from the internal values)or better inletOutlet.
top: fixedValue

jballen August 28, 2006 10:48

Hello, Could someone give m
 
Hello,

Could someone give me an example of using the findNearestBoundaryFace function, given a coordinate location.

Thanks,
Jeff


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