How to refine around the free surface?

Lukan · May 18, 2012, 16:37

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

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

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.

May 18, 2012, 16:37	How to refine around the free surface?	#1
Lukan New Member Kan Wang Join Date: May 2012 Posts: 5 Rep Power: 13	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

May 20, 2012, 07:20		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,697 Rep Power: 143	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. granzer likes this.

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May 19, 2012, 07:15		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,697 Rep Power: 143	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?

May 20, 2012, 19:04		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,697 Rep Power: 143	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.