[Other] Non-conformal mesh in fluent_create/edit mesh interface option

eeLio · February 5, 2018, 07:11

Dear all,

I am writing regarding a question I was asked by fluent (17.2) just before starting a create mesh interface (Mesh Interfaces>Create/Edit) by enabling a "Matching" on "Interface Options". The question was:

The area difference between the interface zones is 2.98%. This could adversely affect your solution. Do you want to proceed?

Do you know anything about that?

Basically my domain consists of two parts: a tank (outer domain) and a turbine cylindrical domain (inner domain). Interfaces between these two domains are non-conformal. I need fluent sees these interfaces as interior.

Do I need to create any mesh interfaces in order to enable that?

Thanks in advance

Fred

Far · February 5, 2018, 11:38

yes you need to create interface between two domains without any option enabled.

Touré · June 6, 2019, 19:02

Absolutely, you need to create a mesh interface. You must select matching when creating the mesh interface in Fluent to have interior zones generated if you have interface mismatch (Do not select Coupled wall otherwise there won't be no flow between the two fluid zones. Do not select mapped because it comes with coupled wall automatically). See ref https://www.sharcnet.ca/Software/Ans...70007.4.1.html

The warning "The area difference between the interface zones is 2.98%" is the difference between the interface surface of the tank and the interface surface of the turbine. Either the meshing refining is quite different on the two interface faces or your two geometries are a little different in terms of diameter, lenght or position (small mismatch when one surface of the interface is projected on the other one). However, there always going to have small gaps between the small elements on one side and bigger elements on the other side of the interface.

Note: Be careful with non-conformal mesh with high sizing ratio between the two zones because of the huge pressure errors at the interface.

February 5, 2018, 07:11	Non-conformal mesh in fluent_create/edit mesh interface option	#1
eeLio New Member Federico Join Date: Sep 2017 Posts: 13 Rep Power: 9	Dear all, I am writing regarding a question I was asked by fluent (17.2) just before starting a create mesh interface (Mesh Interfaces>Create/Edit) by enabling a "Matching" on "Interface Options". The question was: The area difference between the interface zones is 2.98%. This could adversely affect your solution. Do you want to proceed? Do you know anything about that? Basically my domain consists of two parts: a tank (outer domain) and a turbine cylindrical domain (inner domain). Interfaces between these two domains are non-conformal. I need fluent sees these interfaces as interior. Do I need to create any mesh interfaces in order to enable that? Thanks in advance Fred

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February 5, 2018, 11:38		#2
Far Senior Member Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,558 Blog Entries: 6 Rep Power: 54	yes you need to create interface between two domains without any option enabled.

June 6, 2019, 19:02		#3
Touré Member Guiliguili Join Date: Aug 2010 Location: Montréal Posts: 97 Rep Power: 16	Absolutely, you need to create a mesh interface. You must select matching when creating the mesh interface in Fluent to have interior zones generated if you have interface mismatch (Do not select Coupled wall otherwise there won't be no flow between the two fluid zones. Do not select mapped because it comes with coupled wall automatically). See ref https://www.sharcnet.ca/Software/Ans...70007.4.1.html The warning "The area difference between the interface zones is 2.98%" is the difference between the interface surface of the tank and the interface surface of the turbine. Either the meshing refining is quite different on the two interface faces or your two geometries are a little different in terms of diameter, lenght or position (small mismatch when one surface of the interface is projected on the other one). However, there always going to have small gaps between the small elements on one side and bigger elements on the other side of the interface. Note: Be careful with non-conformal mesh with high sizing ratio between the two zones because of the huge pressure errors at the interface.