[DesignModeler] Internal face normal direction

Aidan.CFD · February 12, 2018, 14:38

Hi guys,

Is there any way to 'fix' the normal direction of an internal face? I am doing a 2d axisymmetric fan simulation and am trying to do an optimisation but the fan boundary condition keeps flipping directions as the normal direction keeps flipping. From what I've read, there is a 50-50 chance of what direction will be the normal with an internal face.

Thanks in advance for the help!

bpulat · February 13, 2018, 04:47

Hey Aidan,

If you are using SpaceClaim for your geometry or if you can access it, then it is really easy.
This link will help you out.
http://help.spaceclaim.com/2015.0.0/...ing_Normal.htm

Baris

siw · February 13, 2018, 06:38

A surface (2D) body will have a normal and in DesignModeler you can use Tools/Surface Flip to change the surface normal direction if you want to change it. I've not seen a feature in DM to "fix" the surface normal direction as why would DM change it. Are you sure this is a DM problem, as you've post in the ANSYS Meshing & Geometry forum? I assume you are using Fluent as you said a fan boundary condition, is it not the CFD application doing this and that's where the issue must be resolved?

Aidan.CFD · February 14, 2018, 14:35

Quote:

Originally Posted by siw

A surface (2D) body will have a normal and in DesignModeler you can use Tools/Surface Flip to change the surface normal direction if you want to change it. I've not seen a feature in DM to "fix" the surface normal direction as why would DM change it. Are you sure this is a DM problem, as you've post in the ANSYS Meshing & Geometry forum? I assume you are using Fluent as you said a fan boundary condition, is it not the CFD application doing this and that's where the issue must be resolved?

Thanks for the response! Yes I am using fluent, but from what I understand the fan boundary condition direction is already decided by the geometry/mesh before I get to fluent. The fan boundary condition takes the the 'zone-averaged direction' as its direction, which for the 2D case is a line segment. I can't seem to find how the 'zone-averaged direction' is defined but I am assuming for a 2D line it takes the surface normal?

February 12, 2018, 14:38	Internal face normal direction	#1
Aidan.CFD New Member Join Date: Dec 2017 Posts: 6 Rep Power: 8	Hi guys, Is there any way to 'fix' the normal direction of an internal face? I am doing a 2d axisymmetric fan simulation and am trying to do an optimisation but the fan boundary condition keeps flipping directions as the normal direction keeps flipping. From what I've read, there is a 50-50 chance of what direction will be the normal with an internal face. Thanks in advance for the help!

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February 13, 2018, 04:47		#2
bpulat Member Baris PULAT Join Date: Sep 2016 Location: Italy Posts: 59 Rep Power: 9	Hey Aidan, If you are using SpaceClaim for your geometry or if you can access it, then it is really easy. This link will help you out. http://help.spaceclaim.com/2015.0.0/...ing_Normal.htm Baris

February 13, 2018, 06:38		#3
siw Senior Member Stuart Join Date: Jul 2009 Location: Portsmouth, England Posts: 733 Rep Power: 25	A surface (2D) body will have a normal and in DesignModeler you can use Tools/Surface Flip to change the surface normal direction if you want to change it. I've not seen a feature in DM to "fix" the surface normal direction as why would DM change it. Are you sure this is a DM problem, as you've post in the ANSYS Meshing & Geometry forum? I assume you are using Fluent as you said a fan boundary condition, is it not the CFD application doing this and that's where the issue must be resolved?