error due to isolated region

yaseen wsu · July 12, 2017, 15:29

I want to simulate flow over the weir, the fluid domain consists three parts, at the beginning the solver show error, this is due to isolated region between parts, How can I solve solve this problem.
note: I know by making the domain into one solid part this problem can be overcome, but this way is not good for applying different mesh size.

Opaque · July 12, 2017, 17:41

An isolated region is a symptom of an incorrect set of boundary conditions. It seems you got a volume that is not connected to the other two.

yaseen wsu · July 13, 2017, 02:03

Thanks for your reply
As I understood from you, you want to say that there is space between two parts, (during geometry creation)

ghorrocks · July 13, 2017, 06:28

Either there is a gap between the parts or you did not join the parts together. They can be joined together a number of ways:
* The mesh can be made contiguous, this is done in the mesher and no solver interface is required.
* If the mesh matches 1:1 then use a 1:1 interface.
* If the mesh does not match then use a GGI interface.

yaseen wsu · July 14, 2017, 06:57

thanks a lot Glenn for your reply
just, the second solution what do you mean by 1:1 interface? how can be done? I use ANSYS ICEM for meshing

ghorrocks · July 14, 2017, 07:06

A 1:1 interface requires the mesh matches perfectly at the interface, but they are separate mesh regions. Then in CFX pre you join them with a 1:1 interface.

yaseen wsu · July 19, 2017, 06:49

Quote:

Originally Posted by ghorrocks

A 1:1 interface requires the mesh matches perfectly at the interface, but they are separate mesh regions. Then in CFX pre you join them with a 1:1 interface.

till now the problem does not solved, I think the problem does not related to gap between parts.

https://www.cfd-online.com/Forums/at...1&d=1500461260
https://www.cfd-online.com/Forums/at...1&d=1500461284

ghorrocks · July 19, 2017, 07:21

The mesh is not necessarily joined even if there is no gap. You need to put interfaces into connect the mesh bodies, as I stated in post #4.

yaseen wsu · July 20, 2017, 06:38

[QUOTE=ghorrocks;657609] yes, thanks for your reply I understood

July 12, 2017, 15:29	error due to isolated region	#1
yaseen wsu Senior Member yaseen Join Date: Oct 2015 Location: Hawler Posts: 174 Rep Power: 10	I want to simulate flow over the weir, the fluid domain consists three parts, at the beginning the solver show error, this is due to isolated region between parts, How can I solve solve this problem. note: I know by making the domain into one solid part this problem can be overcome, but this way is not good for applying different mesh size.

July 12, 2017, 17:41		#2
Opaque Senior Member Join Date: Jun 2009 Posts: 1,804 Rep Power: 32	An isolated region is a symptom of an incorrect set of boundary conditions. It seems you got a volume that is not connected to the other two. yaseen wsu likes this.

July 14, 2017, 07:06		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	A 1:1 interface requires the mesh matches perfectly at the interface, but they are separate mesh regions. Then in CFX pre you join them with a 1:1 interface. yaseen wsu likes this.

July 19, 2017, 07:21		#8
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	The mesh is not necessarily joined even if there is no gap. You need to put interfaces into connect the mesh bodies, as I stated in post #4. yaseen wsu likes this.

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July 13, 2017, 02:03		#3
yaseen wsu Senior Member yaseen Join Date: Oct 2015 Location: Hawler Posts: 174 Rep Power: 10	Thanks for your reply As I understood from you, you want to say that there is space between two parts, (during geometry creation)

July 13, 2017, 06:28		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	Either there is a gap between the parts or you did not join the parts together. They can be joined together a number of ways: * The mesh can be made contiguous, this is done in the mesher and no solver interface is required. * If the mesh matches 1:1 then use a 1:1 interface. * If the mesh does not match then use a GGI interface. yaseen wsu likes this.

July 14, 2017, 06:57		#5
yaseen wsu Senior Member yaseen Join Date: Oct 2015 Location: Hawler Posts: 174 Rep Power: 10	thanks a lot Glenn for your reply just, the second solution what do you mean by 1:1 interface? how can be done? I use ANSYS ICEM for meshing

July 20, 2017, 06:38		#9
yaseen wsu Senior Member yaseen Join Date: Oct 2015 Location: Hawler Posts: 174 Rep Power: 10	[QUOTE=ghorrocks;657609] yes, thanks for your reply I understood