Learning Forum

[lancer]

Hello, I'm currently performing simulation where fluid-fluid contact and fluid - solid contact is consider. I just want clarification because no matter how many time I tried I cannot get the same answer as a paper I read. It has 30+% difference. So now I consider I am doing something wrong.

Method and Controls: Doesn't seem do that much except help to stablize the residual chart or any chart.

Materials, Models and Cell Zone Condition is suppose to be accurate as I followed the other paper.

Boundary Condition doesn't seem to change much of the result.

So now I am considering, my porous walls. I don't know if I am doing it right. So first I did "Form new Part", this help as the meshing is easily done. But, according to the paper I read, the fluid-fluid contact is suppose to be an Interface. So I use, Boolean's, but the meshing doesn't align. Next I tried, Automatic Contact Region, this also make the mesh don't align. So how do I make permeable fluid-fluid contact?

[Rob]

 

Some pictures will help. A non-mixing fluid to fluid boundary may be called an interface or a free surface. However, an interface boundary in Fluent is a cell boundary where the two (or more) meshes don’t align. Without knowing whether you’re using the terms in the same way I am, and without knowing what you’re comparing I have no idea what you’ve done, whether it’s correct (in the software) or whether it replicates the paper. 

To create a conformal boundary use Share Topology in SpaceClaim. 

 

[lancer]

Above when i used Form New part in Geoemtry, and the condition I already set in the picture. Please look through.

This one happen when I used Share Topology in Geometry, the meshing between bodies doesn't align as you can see in the pic and there is 4 overlapping region. is that a problem?

This one when I used create using Boolean in Geometry, some mesh align while some don't. There is also overlapping region.

 

Which one best used for my case as shown in the first picture?

[Rob]

The top mesh looks to the better one. The boundary between fluid regions should be an interior in Fluent, and flow will pass straight through them. A wall is (generally) non-permeable and is used to stop flow but (generally) allow heat transfer. I think you may want to go through the geometry, meshing and solver tutorials to see how the process works.