[francesco_b]

Hi Christian,

thank you for your test, I'm cleaning my BC and soon I'll send you it through mail, I'm sorry but I'm not able to attach files in the forum.

I'm having other tests too, so please be patient and don't worry, I'll send you the mail ;)

Regards

Francesco

[aerovargas]

Hi All,

I'm trying to inject air through a jet into an incomig flow using the VOF solver (interFoam). I filled my domain with gamma=1. How do I specify gamma=0 at the jet inlet,

[billy]

Hi,

The boundary condition should switch gradually between wall and permeable wall. I think if you just jump from a permeable wall to a non-permeable wall at gamma = 0.5 you will have numerical problems.

One way could be to multiply the flux out that wall by (1-gamma) but the correct adjustments have to be made to assure mass conservation.

[awacs]

Dear Francesco,

Good job. I am a new Foamer and very interested in this kind of boundary condition.
I tried to create "filter" from "outletInlet" under your guidance in :
http://www.cfd-online.com/Forums/ope...condition.html

but failed and got following errors:
In file included from filterFvPatchField.H:153,
from filterFvPatchFields.H:30,
from filterFvPatchFields.C:29:
/usr/include/bits/mathcalls.h: In member function ‘virtual void Foam::filterFvPatchField<Type>::updateCoeffs()’:
/usr/include/bits/mathcalls.h:265: error: too few arguments to function ‘double gamma(double)’
filterFvPatchField.C:135: error: at this point in file
filterFvPatchField.C:135: error: expected primary-expression before ‘>’ token

How did you implement this new boundary condition? Would you mind giving me some suggestions.

Thanks in advance.

Jitao Liu

[mahaputra]

Originally Posted by caw

Francesco,

i have a simple test case for you. Here is an image:

There is a circular inlet at the lower end of the cavity, there i fluid (gamma = 1) is injected into the cavity. The grey surface is called wall and behaves like a wall. The green surface is called outlet but defined as wall for now. The blue surface is called upper_outlet and acts as an outlet. So in the simulation the fluid level rises with advancing time against gravity.

For your case i would suggest to switch the upper_outlet to wall. Then use your new BC for the surface called outlet. Now, fluid two should be able to leave the domain while the injected fluid one is held back and rises in the same way as mentioned above.

The test case for interFoam is to large to post it here. If you want it, just drop me an email.

Would you please share your BC so a can perform some tests as well?

Thanks and regards
Christian

Dear Christian Winkler


just wondering

how yo managed to display the geometry on the post processing as a transparent image /walls (like you shown above) ?

you did by paraview? could you please tell us, step by step to display transparant walls?


thanks

[caw]

Hi,

this is quite simple. I used paraview under windows.
1 run foamToVTK
2 load your wall data, load your field data
3 for your wall data set opacity to a value below 1.0
4 create a iso surface with value 0.5 for gamma for your field data

actually thats it....

best regards
Christian

[awacs]

Dear Francesco,

Thanks a lot for your filter BC. I have tested it for several weeks.

I want to know what's the difference between

if (gammap[id]<0.001) this->valueFraction()[id] = 0;
or
if (gammap[id]<0.5) this->valueFraction()[id] = 0;

or sth. like this.

Please do me a fever.

Moreover, is it necessary to use the filterU BC for velocity and filterP BC for pressure at the same time, or , just use one of them ?

Would you mind sending me a tutorial about how to use the filter BC ?

My e-mail address is:

liujitao@mail.sdu.edu.cn

Thanks and regards

Jitao

[Andrea_85]

Dear Francesco,
I'm also interested is this kind of boundary condition. I'm working with multiphase flow and i'm facing many problem with outlet condition, maybe your BC could do the job i want. This thread is quite old, but can you share/send me the implementation of this boudary condition?.
my email is andrea.ferrari@unil.ch

Best Regards
andrea