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-   -   Selective outlet boundary condition for InterFoam (http://www.cfd-online.com/Forums/openfoam-solving/59146-selective-outlet-boundary-condition-interfoam.html)

caw December 21, 2007 05:30

Dear FOAMers, just before c
 
Dear FOAMers,

just before christmas there is one problem that haunts me night by night ;-)
So any help is highly appreciated.

A two phase flow problem, which can be handled by interFoam quite well, is the basic thing.
I am looking for a way to prevent fluid 1 leaving the flow domain at an outlet while fluid 2 can pass through.

-A quite complicated way to do this would be to move faces from the outlet-bc to a wall-bc if gamma is > 0 in the adjacent cell.

-Or is there a way to force the flux to zero on those faces (not the whole path of course)?

Any hints?


Thanks in advance and have a nice holiday season

kind regards
Christian

hjasak December 21, 2007 05:47

Are you sure this is what you
 
Are you sure this is what you want?

If so, take a mixed boundary condition and manipulate the fixed value-fixed gradient switch based on gamma. It would be easiest just to write a new fvPatchField class.

Enjoy,

Hrv

caw December 21, 2007 06:48

Thanks Hrv for your fast reply
 
Thanks Hrv for your fast reply.

Actually i dont know what i want...just some clues for the most efficient solution i suppose ;-))

I will look into the existing fvPatchField classes...that was probably the hint i was looking for.

Kind regards
Christian

francesco_b February 11, 2008 10:43

Hi, I've tried to make this
 
Hi,

I've tried to make this boundary condition, but I've got some issues concerning the switch, can you pls help me with the implementation?

The function should be something like

template<class>
void filterFvPatchField<type>::updateCoeffs()
{
if (this->updated())
{
return;
}
const volScalarField& gammap = gamma
(
reinterpret_cast<double>(NULL)
);

this->valueFraction() = 0.0;

for (int i = 0; i < boundarysize; i++)
{
if (gammap(cellnexttoboundary(i)) > 0.5)
{
this->valueFraction(i) = 1.0;
}
}

mixedFvPatchField<type>::updateCoeffs();
}

I've got this questions:

1) Is the initialization of gammap correct? If it is not, how should it be?
2) What is the name of the variable which gives me "boundarysize"?
3) What should I write to obtain the value of gammap(cellnexttoboundary(i))?
4) Is there a better way of doing this?

As I said before, I'm new to C++, I know these are stupid questions but for me it is not so clear,

Thanks in advance

Francesco

awacs May 29, 2009 23:42

Quote:

Originally Posted by francesco_b (Post 180458)
Hi,

I've tried to make this boundary condition, but I've got some issues concerning the switch, can you pls help me with the implementation?

The function should be something like

template<class>
void filterFvPatchField<type>::updateCoeffs()
{
if (this->updated())
{
return;
}
const volScalarField& gammap = gamma
(
reinterpret_cast<double>(NULL)
);

this->valueFraction() = 0.0;

for (int i = 0; i < boundarysize; i++)
{
if (gammap(cellnexttoboundary(i)) > 0.5)
{
this->valueFraction(i) = 1.0;
}
}

mixedFvPatchField<type>::updateCoeffs();
}

I've got this questions:

1) Is the initialization of gammap correct? If it is not, how should it be?
2) What is the name of the variable which gives me "boundarysize"?
3) What should I write to obtain the value of gammap(cellnexttoboundary(i))?
4) Is there a better way of doing this?

As I said before, I'm new to C++, I know these are stupid questions but for me it is not so clear,

Thanks in advance

Francesco

Dear Francesco,

I am also confused on this issue. How did you retrieve the value of gamma in the cell close to the boundary patch? How to write valueFraction as a function of gamma?
I am a newbie in OpenFOAM. Please give me some tips.:)

Thanks in advance.

Jitao Liu

ziglat2004 February 7, 2012 14:48

Hi,

I have the same problem in Fluent. do you know how to define the "filter" boundary condition in fluent?

Thanks


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