OpenLB – Open Source Lattice Boltzmann Code Forums on OpenLB General Topics Problem about free energy model

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• #5454
KaiLin
Participant

Hi,

we modified the example case of contactAngle2d and found two problems.

1. When we use xml file to import the positions of nodes, it can be run properly under 20000 nodes. But when the number of nodes is over 20000, the program stop before “Prepare Geometry … OK”. Is there a limit of importing nodes with xml file or the superGeometry is limited? Is there any other way that we can import complex geometry with 2D?

2. When we use free energy model，we set material number 2 with setFreeEnergyWallBoundary, material number 1 with bulkDynamics. We find(The number irepresents material number)

Not converge Converge
1 2 1 1 2 2 1
1 2 1 1 2 2 1
1 2 1 1 2 2 1

We set the parameters with contact angele 46 degree.
Fluid can’t wet over the block Fluid can wet over the block
1 1 1 1 1 1 1 1 1
1 2 2 1 1 2 2 2 1
1 2 2 1 1 2 0 2 1
1 1 1 1 1 2 2 2 1
1 1 1 1 1

#5455
KaiLin
Participant

Later part is not shown properly.

Not converge
1 2 1
1 2 1
1 2 1

Converge
1 2 2 1
1 2 2 1
1 2 2 1

We set the parameters with contact angele 46 degree.
Fluid can’t wet over the block
1 1 1 1
1 2 2 1
1 2 2 1
1 1 1 1

Fluid can wet over the block
1 1 1 1 1
1 2 2 2 1
1 2 0 2 1
1 2 2 2 1
1 1 1 1 1

Thanks for your kind reply with email yesterday! Finally I can speak at the forum ^_^

Regards,
Kai Lin

#5456
KaiLin
Participant

I correct the distribution of material number. Could you please tell me why? Thx!

Not converge
. . .
. . .
2 1 2
2 1 2
2 1 2
2 1 2
2 1 2
2 1 2
. . .
. . .

Converge
. . . .
. . . .
2 1 1 2
2 1 1 2
2 1 1 2
2 1 1 2
2 1 1 2
2 1 1 2
. . . .
. . . .

#5457
mathias
Keymaster

Yes, that (situation above) are too few fluid nodes.

• This reply was modified 3 years, 5 months ago by mathias.
#5458
KaiLin
Participant

Hi Mathias,

Sorry, I don’t understand what means “too fee fluid nodes”, >_<

We want to build a model of a two-phase flow(liquid and air) in porous media. In porous media the situation of fluid with one layer lattice is usual. So it’s easy to lead no converge.

Not converge
. . .
2 1 2
2 1 2
2 1 2
. . .

Does it mean we must make sure there are fluid with at least two layer lattice in whole geometry. Really need the help of your team! Thank you!

Regards,
Kai Lin

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