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-   -   VOF-Simulation (http://www.cfd-online.com/Forums/openfoam/77046-vof-simulation.html)

ronaldo June 11, 2010 03:16

VOF-Simulation
 
could someone please send me an example of VOF-Simulation (Water and Air) or Tutorial?
Thank you in advance

akidess June 11, 2010 03:55

Whats wrong with the dam break tutorial in OpenFOAM?

l_r_mcglashan June 11, 2010 04:24

Like this (2D) air bubble rising in water?

http://people.pwf.cam.ac.uk/lrm29/files/movie.gif

ronaldo June 11, 2010 05:14

hi linespoints,

could you please send me an example of VOF-simulation 3D using OpenFoam?


Thanks you in advance.

nimasam June 11, 2010 08:46

interFoam
 
hi foamer
i simulated a 2d axisymmetric and a 3D modeling of bubble rising
but it seems there is some thing wrong with open foam, instead of bubble rising, bubble collapses down.
gravity is in -y direction

i used these BC's in 2D case it works well but in 3D and 2D axisymmetric,
it doesn't work

sinohe March 9, 2012 02:59

3D bubble rising
 
Hi dear nimasam

I have the same problem as you. if you or anyone know the solution help me please to get out of this.


thanks in advanced

nimasam March 9, 2012 05:03

hi dear navid
there is no bug, it returns into the boundary condition and mesh size
so
1) use finer mesh
2) use zerGradient for velocity everywhere else the bottom of geometry which uses a fixedValue uniform (0 0 0)

P.S
you can post your email in private for me, then i will send you a case test and some refrences

liguifan April 14, 2013 00:31

Hello,

I met the same problem for the 2D case. For the same boundary condition, 3D works well but 2D works very different. I am simulating a droplet of oil on surface of water. For the 2D case, I set the velocity of leftWall and righWall and lowerWall (0 0 0), but it behaves very different with the 3D situation.

Just wondering why we need to use zeroGradient for the leftWall and righWall .But in the damBreak tutorial, the velocity is for leftWall and rightWall is set to (0 0 0). Can you please explain this?

Thanks in advance!

Quote:

Originally Posted by nimasam (Post 348504)
hi dear navid
there is no bug, it returns into the boundary condition and mesh size
so
1) use finer mesh
2) use zerGradient for velocity everywhere else the bottom of geometry which uses a fixedValue uniform (0 0 0)

P.S
you can post your email in private for me, then i will send you a case test and some refrences


nimasam April 14, 2013 00:59

those cases are different from each others, in dambreak those surfaces are wall, so you apply a no slip boundary condition, but here in bubble rising test case, those surace are not wall, its an imaginary boundary which split our test case domain with the rest of stagnant liquid

liguifan April 14, 2013 16:59

Thanks very much for the quick reply.

I still unsure about the boundary condition for my case.

I try to simulate a droplet of oil in the central of a cylinder water with a radius of 0.09m base, and now i want to simulate it as a asymmetrical 2D case. So in 2D case, the droplet should be split into half at r=0. As you said, I can set the boundary condition for my rightWall( the cylinder boundary in 3D and at radius =0) as zeroGradient in velocity, but I am not sure how to set the boundary condition for the leftWall? Do you have some suggestions?

Thanks!

Kind regards,




Quote:

Originally Posted by nimasam (Post 420361)
those cases are different from each others, in dambreak those surfaces are wall, so you apply a no slip boundary condition, but here in bubble rising test case, those surace are not wall, its an imaginary boundary which split our test case domain with the rest of stagnant liquid


liguifan April 14, 2013 18:28

5 Attachment(s)
I also tried to use the zeroGradient boundary condition set in velocity.
Quote:

dimensions [0 1 -1 0 0 0 0];

internalField uniform (0 0 0);

boundaryField
{
leftWall
{
type zeroGradient;
//value uniform (0 0 0);
}
rightWall
{
type zeroGradient;
//value uniform (0 0 0);
}
lowerWall
{
type fixedValue;
value uniform (0 0 0);
}
atmosphere
{
type fluxCorrectedVelocity;
value uniform (0 0 0);
}
defaultFaces
{
type empty;
}
}
However, water seems to leak out after a few steps as in the graphs. In this case, I initial a cylinder oil on the surface of the water.

Could you please give me some suggestion about where I am wrong?

Many thanks!


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