[ICEM] unwanted merged two boundary conditions?

ehsan.bakhtiari · October 11, 2021, 16:40

A computational domain around a 2D airfoil is considered.

A structural mesh with associated block edges is generated.

The pressure and suction sides of the airfoil are desired to be separated.

Before performing the "Convert to Unstruct Mesh" action, everything looks fine: The two parts and their boundary conditions are distinct.

The problem is: once the mesh is converted into Unstruct Mesh to create the *.uns file, both sides of the airfoil are merged, and only the suction-side BC appears in FLUENT containing the both BCs; while the pressure-side BC disappears and the two sides of the airfoil are not individually selectable.

So, what's the problem in ICEM?

Best Regards,
E. B

siw · October 12, 2021, 05:05

Did you put the suction side edge and pressure side edge into separate PARTS? Have you watched the ICEM tutorial videos https://www.youtube.com/watch?v=6wQPeBpvwCk

ehsan.bakhtiari · October 12, 2021, 11:39

Quote:

Originally Posted by siw

Did you put the suction side edge and pressure side edge into separate PARTS? Have you watched the ICEM tutorial videos https://www.youtube.com/watch?v=6wQPeBpvwCk

Thanks, Stuart
Yes; as I said before, before converting to "Unstruct Mesh", there are two parts representing both the airfoil sides, and also the BCs are correctly related to each part.
Once the mesh is converted, there are still two parts in the list of parts, but in the boundary condition tab, both sides are merged for the suction side and the pressure side remained unchanged. Meanwhile, in FLUENT only the suction side (the merged BC) is shown and the pressure side is gone!

ehsan.bakhtiari · October 14, 2021, 15:53

I've found the solution.
The problem was from associating the block edges.
For a typical airfoil section, of which the trailing edge is not blunt, there must be at least three blocks to create a structural mesh: pressure and suction-sides and also the leading edge.
Once the edge of the block containing the leading edge is associated with both the pressure and suction-side curves, ICEM will automatically merge both the curves of the airfoil.
The solution is to split the block related to the leading edge and then, re-associate the edge to corresponding curves. Then, it would result in two correct separate wall-BCs.
Hopefully, it would help researchers in the future.

October 11, 2021, 16:40	unwanted merged two boundary conditions?	#1
ehsan.bakhtiari New Member ehsan bakhtiari Join Date: May 2016 Posts: 13 Rep Power: 9	A computational domain around a 2D airfoil is considered. A structural mesh with associated block edges is generated. The pressure and suction sides of the airfoil are desired to be separated. Before performing the "Convert to Unstruct Mesh" action, everything looks fine: The two parts and their boundary conditions are distinct. The problem is: once the mesh is converted into Unstruct Mesh to create the *.uns file, both sides of the airfoil are merged, and only the suction-side BC appears in FLUENT containing the both BCs; while the pressure-side BC disappears and the two sides of the airfoil are not individually selectable. So, what's the problem in ICEM? Best Regards, E. B

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October 12, 2021, 05:05		#2
siw Senior Member Stuart Join Date: Jul 2009 Location: Portsmouth, England Posts: 733 Rep Power: 25	Did you put the suction side edge and pressure side edge into separate PARTS? Have you watched the ICEM tutorial videos https://www.youtube.com/watch?v=6wQPeBpvwCk

October 14, 2021, 15:53		#4
ehsan.bakhtiari New Member ehsan bakhtiari Join Date: May 2016 Posts: 13 Rep Power: 9	I've found the solution. The problem was from associating the block edges. For a typical airfoil section, of which the trailing edge is not blunt, there must be at least three blocks to create a structural mesh: pressure and suction-sides and also the leading edge. Once the edge of the block containing the leading edge is associated with both the pressure and suction-side curves, ICEM will automatically merge both the curves of the airfoil. The solution is to split the block related to the leading edge and then, re-associate the edge to corresponding curves. Then, it would result in two correct separate wall-BCs. Hopefully, it would help researchers in the future.