Gmsh 3.0 - Boundary layer 3D mesh

PaulBet · April 14, 2018, 03:50

Dear all,
I just begin to use Gmsh and I have some problems with the last version. I searched some solutions on forums or in the documentation but I still have some problems :

I am trying to use Gmsh to mesh 3D models by taking into account the boundary layer.

My 3D model is from a .STP file and I tried to use the GUI to generate meshes.
I have no problems to generate 3D meshes which are well exported to OpenFoam.

Now, I want ton add some prisms layers at walls to take into account the boundary layer.
I followed all the information that I've found on forums or documentation but it seems that nothing happens when I use
Mesh -> Define -> Size Fields -> New -> Boundary Layer (with the GUI).

I have no errors in the dialog window below, but I have no changes in the mesh...

I think the reason is that I don't fill the fields with good information, especially about EdgesList and NodesList ??
I try to apply layers of prisms on surfaces (as I have a 3D model...) and I am not sure what is expected in these fields (and what is the format (1, 2, ... ?). I have noticed the values of each surface but I don't know how to input them in the fields...

My questions :
- Is there a good tutorial for Gmsh and is there a method described with tutorials or examples about how to do these kinds of meshing or operations ?
- How can I input the expected informations about faces selected, ... in the Boundary Layer window fields (format, ...) ?

Thank you very much in advance for your help and answers,
Best regards,
Paul

PaulBet · April 17, 2018, 04:30

Hello,

It is not the solution that I hoped but I think it's the right solution (?) :
If someone is interested, I will post a more detailled message but I finally used Engrid with a surface mesh from Gmsh (file .msh).
Engrid is very efficient and allows to create a prismatic boundary layer easily, almost as easily as for commercial software.

I will try to improve the method and I will come back to detail it...

But if someone has other method based on Gmsh, I am still interested...

AlbertoPi · April 19, 2018, 16:16

Hi
Boundary Layer Field only works with 2D grids. You have to use 'extrude' commands for 3D problems.

Regards

April 14, 2018, 03:50	Gmsh 3.0 - Boundary layer 3D mesh	#1
PaulBet New Member Paul Bertrand Join Date: Apr 2018 Location: France Posts: 8 Rep Power: 8	Dear all, I just begin to use Gmsh and I have some problems with the last version. I searched some solutions on forums or in the documentation but I still have some problems : I am trying to use Gmsh to mesh 3D models by taking into account the boundary layer. My 3D model is from a .STP file and I tried to use the GUI to generate meshes. I have no problems to generate 3D meshes which are well exported to OpenFoam. Now, I want ton add some prisms layers at walls to take into account the boundary layer. I followed all the information that I've found on forums or documentation but it seems that nothing happens when I use Mesh -> Define -> Size Fields -> New -> Boundary Layer (with the GUI). I have no errors in the dialog window below, but I have no changes in the mesh... I think the reason is that I don't fill the fields with good information, especially about EdgesList and NodesList ?? I try to apply layers of prisms on surfaces (as I have a 3D model...) and I am not sure what is expected in these fields (and what is the format (1, 2, ... ?). I have noticed the values of each surface but I don't know how to input them in the fields... My questions : - Is there a good tutorial for Gmsh and is there a method described with tutorials or examples about how to do these kinds of meshing or operations ? - How can I input the expected informations about faces selected, ... in the Boundary Layer window fields (format, ...) ? Thank you very much in advance for your help and answers, Best regards, Paul

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April 17, 2018, 04:30		#2
PaulBet New Member Paul Bertrand Join Date: Apr 2018 Location: France Posts: 8 Rep Power: 8	Hello, It is not the solution that I hoped but I think it's the right solution (?) : If someone is interested, I will post a more detailled message but I finally used Engrid with a surface mesh from Gmsh (file .msh). Engrid is very efficient and allows to create a prismatic boundary layer easily, almost as easily as for commercial software. I will try to improve the method and I will come back to detail it... But if someone has other method based on Gmsh, I am still interested...

April 19, 2018, 16:16		#3
AlbertoPi New Member Alberto Pizarro Join Date: Feb 2016 Posts: 18 Rep Power: 10	Hi Boundary Layer Field only works with 2D grids. You have to use 'extrude' commands for 3D problems. Regards