Excluding domain boundaries from getting written twice

skrishnamoorthy · May 18, 2016, 18:25

Hello,

I'm using pointwise to generate a 3-D Gmsh structured grid. Think of this grid as two cuboids of different size (one of size 300X300X10, the other of size 300X300X140) with one common face. I want to do two things -

1. This common face needs to have a label associated with it. (say "interface").

2. This face, even though it is a member of both blocks should be written to the mesh file only once, so the full mesh is 300X300X150.

I have tried creating the mesh through extrusion and through creating blocks out of domains but I can't seem to accomplish the goals above. I get a bunch of "unspecified" labels in msh file if I click on "include connections" and my total mesh also ends up becoming 300X300X151, presumably because the internal interface is being included once for each block.

Can someone help me with is?

Thank you!

dgarlisch · May 19, 2016, 11:02

I think I understand the grid you are describing, but please post a pw file or an image of the grid.

Did you apply a BC to the connection domain?

If yes, then the domain will be "inflated" during export. Inflation creates unique (yet coincident) points for each "side" of the domain. That would explain the connection domain being exported twice.

The Gmsh CAE exporter does NOT support non-inflated BC types (yet).

Currently in Pointwise, only the Fluent CAE exporter supports this with the Radiator, Fan, and Porous Jump BC types.

Please log a feature request with Pointwise support if you need this capability in the Gmsh exporter.

skrishnamoorthy · May 19, 2016, 13:44

Hello,

Thanks for your reply! The pw file can be found here:

https://drive.google.com/open?id=0B6...UdzMXl3ek9LY0k

The issue is exactly as you say - I'm trying to attach a label "interface" to the boundary between the two domains. It will either make me attach that label to both instances of the boundary or send one to "unspecified" and the other to "interface". Then when it writes out the mesh, it writes out two copies of the interface, one with the right label, the other with "unspecified". Strangely enough, in the 2D analog of this problem, this does not happen - there, I can choose one instance for the label and the other does not get exported as unspecified.

dgarlisch · May 19, 2016, 14:27

this is a known limitation in the Pointwise Gmsh exporter. No workaround is available.

As I mentioned above, you will need to use the Fluent exporter to stop the inflation of the connection domains.

skrishnamoorthy · May 19, 2016, 14:28

Ok, thank you for the information! I suppose I'll lodge a feature request and then try and deal with this in my own parser.

May 18, 2016, 18:25	Excluding domain boundaries from getting written twice	#1
skrishnamoorthy New Member Siddharth Join Date: Jan 2013 Posts: 6 Rep Power: 13	Hello, I'm using pointwise to generate a 3-D Gmsh structured grid. Think of this grid as two cuboids of different size (one of size 300X300X10, the other of size 300X300X140) with one common face. I want to do two things - 1. This common face needs to have a label associated with it. (say "interface"). 2. This face, even though it is a member of both blocks should be written to the mesh file only once, so the full mesh is 300X300X150. I have tried creating the mesh through extrusion and through creating blocks out of domains but I can't seem to accomplish the goals above. I get a bunch of "unspecified" labels in msh file if I click on "include connections" and my total mesh also ends up becoming 300X300X151, presumably because the internal interface is being included once for each block. Can someone help me with is? Thank you!

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May 19, 2016, 11:02		#2
dgarlisch Senior Member David Garlisch Join Date: Jan 2013 Location: Fidelity Pointwise, Cadence Design Systems (Fort Worth, Texas Office) Posts: 307 Rep Power: 14	I think I understand the grid you are describing, but please post a pw file or an image of the grid. Did you apply a BC to the connection domain? If yes, then the domain will be "inflated" during export. Inflation creates unique (yet coincident) points for each "side" of the domain. That would explain the connection domain being exported twice. The Gmsh CAE exporter does NOT support non-inflated BC types (yet). Currently in Pointwise, only the Fluent CAE exporter supports this with the Radiator, Fan, and Porous Jump BC types. Please log a feature request with Pointwise support if you need this capability in the Gmsh exporter.

May 19, 2016, 13:44		#3
skrishnamoorthy New Member Siddharth Join Date: Jan 2013 Posts: 6 Rep Power: 13	Hello, Thanks for your reply! The pw file can be found here: https://drive.google.com/open?id=0B6...UdzMXl3ek9LY0k The issue is exactly as you say - I'm trying to attach a label "interface" to the boundary between the two domains. It will either make me attach that label to both instances of the boundary or send one to "unspecified" and the other to "interface". Then when it writes out the mesh, it writes out two copies of the interface, one with the right label, the other with "unspecified". Strangely enough, in the 2D analog of this problem, this does not happen - there, I can choose one instance for the label and the other does not get exported as unspecified.

May 19, 2016, 14:27		#4
dgarlisch Senior Member David Garlisch Join Date: Jan 2013 Location: Fidelity Pointwise, Cadence Design Systems (Fort Worth, Texas Office) Posts: 307 Rep Power: 14	this is a known limitation in the Pointwise Gmsh exporter. No workaround is available. As I mentioned above, you will need to use the Fluent exporter to stop the inflation of the connection domains.

May 19, 2016, 14:28		#5
skrishnamoorthy New Member Siddharth Join Date: Jan 2013 Posts: 6 Rep Power: 13	Ok, thank you for the information! I suppose I'll lodge a feature request and then try and deal with this in my own parser.