[Gmsh] Setting a boundary condition on both sides of a surface

STutexas · April 2, 2016, 21:33

Hi

I am using Gmsh to create a geometry that is a cube with a sphere in it. I would like to set a zero gradient BC on the inner surface of the sphere and fixed value BC on the outer surface of the sphere. The outer surfaces of the cube will have fixed value BC here.

But when I create the geometry and input it in openfoam using gmshtofoam, openfoam does not recognize the surface as 2 different boundaries and does not let me set these 2 boundary conditions. Please let me know how I could achieve that.

My .geo file is attached for reference if you want to peruse it.

Thank you.

opedrofunk · April 7, 2016, 12:46

Hi,

I don't know what exactly you are trying to achieve, but you probably just need to create a baffle after importing your mesh to OpenFOAM. It's pretty easy, just check out the createBaffles utility to get started.

And if you're doing multi-region stuff, then you'll probably need to use the splitMeshRegions tool. There are loads of examples both in the tutorials and online for this, so it should be straight forward to adapt them to your case.

Good luck!

Kind regards,
Peter

STutexas · April 8, 2016, 01:00

Hi

Thank you for the help. I was able to create the baffles and run my case. But I am getting an error.

After creating my baffles I get this warning.
'
--> FOAM Warning :
From function createBaffles
in file createBaffles.C at line 773
Setting field on boundary faces to zero.
You might have to edit these fields.

How do I edit the fields. Do I need to use map fields?
Thank you for the help.

Saurabh

STutexas · April 11, 2016, 15:06

I have been able to sort the problem by redefining the values of the fields in the initial file. Now I have to set different initial values of field variable for different cellSets. I tried using setFields and funkySetFields but both approaches failed. Do you have any ideas on how I could do that.

Thanks again for all the help.

Saurabh

opedrofunk · April 11, 2016, 15:24

Hi,
I'm not 100% sure what the issue is, but it sounds like you just need to run a changeDictionary to set the patch types, boundary type, and values for the baffles you've created?
Kind regards,
Peter

April 2, 2016, 21:33	Setting a boundary condition on both sides of a surface	#1
STutexas Member Saurabh Tandon Join Date: Nov 2015 Location: Austin Posts: 43 Rep Power: 10	Hi I am using Gmsh to create a geometry that is a cube with a sphere in it. I would like to set a zero gradient BC on the inner surface of the sphere and fixed value BC on the outer surface of the sphere. The outer surfaces of the cube will have fixed value BC here. But when I create the geometry and input it in openfoam using gmshtofoam, openfoam does not recognize the surface as 2 different boundaries and does not let me set these 2 boundary conditions. Please let me know how I could achieve that. My .geo file is attached for reference if you want to peruse it. Thank you.

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April 7, 2016, 12:46		#2
opedrofunk Member Peter Join Date: Feb 2015 Location: New York Posts: 73 Rep Power: 11	Hi, I don't know what exactly you are trying to achieve, but you probably just need to create a baffle after importing your mesh to OpenFOAM. It's pretty easy, just check out the createBaffles utility to get started. And if you're doing multi-region stuff, then you'll probably need to use the splitMeshRegions tool. There are loads of examples both in the tutorials and online for this, so it should be straight forward to adapt them to your case. Good luck! Kind regards, Peter

April 8, 2016, 01:00		#3
STutexas Member Saurabh Tandon Join Date: Nov 2015 Location: Austin Posts: 43 Rep Power: 10	Hi Thank you for the help. I was able to create the baffles and run my case. But I am getting an error. After creating my baffles I get this warning. ' --> FOAM Warning : From function createBaffles in file createBaffles.C at line 773 Setting field on boundary faces to zero. You might have to edit these fields. How do I edit the fields. Do I need to use map fields? Thank you for the help. Saurabh

April 11, 2016, 15:06		#4
STutexas Member Saurabh Tandon Join Date: Nov 2015 Location: Austin Posts: 43 Rep Power: 10	I have been able to sort the problem by redefining the values of the fields in the initial file. Now I have to set different initial values of field variable for different cellSets. I tried using setFields and funkySetFields but both approaches failed. Do you have any ideas on how I could do that. Thanks again for all the help. Saurabh

April 11, 2016, 15:24		#5
opedrofunk Member Peter Join Date: Feb 2015 Location: New York Posts: 73 Rep Power: 11	Hi, I'm not 100% sure what the issue is, but it sounds like you just need to run a changeDictionary to set the patch types, boundary type, and values for the baffles you've created? Kind regards, Peter