[vatant]

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]

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

[vatant]

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]

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]

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]

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]

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

[vatant]

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]

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]

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]

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]

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]

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]

I guess something like

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

[jballen]

Hello,

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

Thanks,
Jeff