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-   -   How to refine around the free surface? (http://www.cfd-online.com/Forums/cfx/101987-how-refine-around-free-surface.html)

Lukan May 18, 2012 16:37

How to refine around the free surface?
 
Hi all

I am totally a beginner of CFX... Just working at building a wave tank in Ansys mesh, I am thinking of refining around the free surface to obtain more accurate results. Can anybody explain it?

Thank you very much!

Lukan

ghorrocks May 19, 2012 07:15

Do you mean dynamic refinement which follows the surface and changes during the progress of the simulation or generating a mesh with a refined area for the interface, and the mesh does not move throughout the simulation?

Lukan May 19, 2012 09:04

Quote:

Originally Posted by ghorrocks (Post 361961)
Do you mean dynamic refinement which follows the surface and changes during the progress of the simulation or generating a mesh with a refined area for the interface, and the mesh does not move throughout the simulation?

Just want to refine the area of the interface, no need to move the mesh. And I didnt figure out the differences between refined mesh and inflated mesh... Just saw somebody inflated the mesh near the interface? So what's the differences?

ghorrocks May 20, 2012 07:20

These are all just meshing technqiues. Inflation extrudes prisms or hexas our from the surface. This is usually used to get a fine wall mesh to resolve boundary layers, but can also be used to resolve free surfaces. Refinement is a general term for putting a finer mesh in a particular region. You could consider inflation a type of refinement.

Lukan May 20, 2012 15:32

Quote:

Originally Posted by ghorrocks (Post 362028)
These are all just meshing technqiues. Inflation extrudes prisms or hexas our from the surface. This is usually used to get a fine wall mesh to resolve boundary layers, but can also be used to resolve free surfaces. Refinement is a general term for putting a finer mesh in a particular region. You could consider inflation a type of refinement.


Ok, so refinement is just a general idea, including inflation and spacing control. As I know, inflation can only be applied to boundaries, thereby how can I do inflation near free surfaces?

Thank you very much for your patience!!! :):):)

ghorrocks May 20, 2012 19:04

Put a boundary along where you expect the free surface to lie by splitting the block which contains it. When you specify both bits of the block as the same part (in Workbench anyway) you will generate a contiguous mesh with no need for an interface. Then you can apply inflation on the split to get inflation around the free surface.


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