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[ANSYS Meshing] Cartesian cut cell method - interfaces

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Old   November 21, 2016, 07:46
Default Cartesian cut cell method - interfaces
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Rob Vervoort
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For a project I am trying to model a moving fan and the air flow generated by the fan using a sliding mesh.
To be able to use the sliding mesh, interfaces are required at the edges of the fluid domain in which my fan is positioned.

I am currently trying to generate a grid using the cartesian cut cell method (in ANSYS). I made named selections for the faces that are supposed to be interfaces. However during the assembly meshing proces, the faces of the fan zone and the adjacent zone are merged. Therefore it is not possible to create an interface at the intersection of two zones.

Is there a way to create interfaces in a cut cell mesh?

PS: I tried to model the fan using a moving reference frame (moving fan cell zone around z-axis at 94 rad/s) without interfaces at the moving zone. The obtained results are very strange in that case (see attachment). The fan seems to move the air in two directions.
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File Type: jpg fan.jpg (49.2 KB, 86 views)
File Type: jpg mesh_unit.jpg (146.3 KB, 107 views)
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Old   November 21, 2016, 20:22
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in your geometry, click on the body/part which has interface surface.
in the details on left side change "SHARED TOPOLOGY METHOD" from Automatic to Imprints.

This will make sure you have 2 surfaces and they have imprints on each other at connection.

Also give fixed reference and inlet and outlet of fan surface for direction of flow.
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Old   November 22, 2016, 01:58
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Thank you for your reply.
However, the part below is still a bit unclear to me.
It will not be possible to assign an in and outlet to the fan's domain because the interfaces are there.

Quote:
Originally Posted by Kapi View Post
Also give fixed reference and inlet and outlet of fan surface for direction of flow.
Could you explain this in more detail?
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Old   November 22, 2016, 02:34
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Have you assigned faces being interface as named selection in DM or Ansys-Meshing?
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Old   November 22, 2016, 03:02
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I assigned them in ANSYS meshing.
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Old   November 22, 2016, 03:07
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Quote:
Originally Posted by RobV View Post
I assigned them in ANSYS meshing.
actually there is no need to give all faces as named selection.

Contact faces are already interface. there is enough to give remaining faces as named selection.

Here is what you have to do is that you should select ''automatic'' in shared topo in DM. if you use FLUENT as solver, it is going to already recall interfaces, moreover, you dont have to use ''mesh interfaces'' in FLUENT as well.(you could see that in boundary conditions tab, interior, shadow-wall etc.)
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Old   November 22, 2016, 17:20
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Rob,

there should be an interface between
air and fan inlet
also,
fan outlet and air
this way the air knows whr to enter and whr to exit!

I havent modelled what u r modelling but I do use fan without blades with right air flow equation of fan. so my fan is just a box with right boundary conditions.
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Old   November 28, 2016, 03:03
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Quote:
Originally Posted by Kapi View Post
in your geometry, click on the body/part which has interface surface.
in the details on left side change "SHARED TOPOLOGY METHOD" from Automatic to Imprints.

This will make sure you have 2 surfaces and they have imprints on each other at connection.

Also give fixed reference and inlet and outlet of fan surface for direction of flow.
Thanks for the reply but this did not work for me.
When loading the mesh into fluent, fluent keeps removing one of the two interfaces. I really need these interfaces even though some people say I do not. Any suggestions?
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Old   November 28, 2016, 03:25
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Quote:
Originally Posted by RobV View Post
Thanks for the reply but this did not work for me.
When loading the mesh into fluent, fluent keeps removing one of the two interfaces. I really need these interfaces even though some people say I do not. Any suggestions?
could you please use mapped face meshing in all interfaces?
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Old   November 28, 2016, 03:58
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Quote:
Originally Posted by oozcan View Post
could you please use mapped face meshing in all interfaces?
Mapped face sizing is not possible when using the cut-cell method (due to the fact that it is an assembly mesh).
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Old   November 28, 2016, 04:09
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Quote:
Originally Posted by RobV View Post
Mapped face sizing is not possible when using the cut-cell method (due to the fact that it is an assembly mesh).
well, please read my first second post.
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Old   November 28, 2016, 04:29
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I do need interfaces, they are required for MRF and Sliding Mesh methods.
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Old   November 28, 2016, 04:30
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Quote:
Originally Posted by RobV View Post
I do need interfaces, they are required for MRF and Sliding Mesh methods.
ok, you need to do second post I have written,
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Old   November 28, 2016, 13:18
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Quote:
Originally Posted by oozcan View Post
actually there is no need to give all faces as named selection.

Contact faces are already interface. there is enough to give remaining faces as named selection.

Here is what you have to do is that you should select ''automatic'' in shared topo in DM. if you use FLUENT as solver, it is going to already recall interfaces, moreover, you dont have to use ''mesh interfaces'' in FLUENT as well.(you could see that in boundary conditions tab, interior, shadow-wall etc.)
You write that I don't require interfaces. I know that ansys meshing automatically makes contact regions when making the assembly mesh. I however, want to assign them manually in Fluent (because it is required when I want to model a moving zone). Did anyone succeed to make interfaces for a (cutcell) assembly mesh?
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Old   May 30, 2017, 08:20
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hi Rob. Did u manage to figure out how to create interfaces in cutcell mesh?
I am getting the same problem, thx
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