Exercise on 2d meshing

[johnwang]

Hi,

1. Open a New document, Use attached marco to make a triangle with Face. Its name in mode tree is Shape. Save it. I saved it as d:/cfdtest/aFace.FCstd
2. Switch to FEA WB, click A icon to active FEA tool
3. Click to select Shape in mode tree, Mesh tool is activated.
4. Cick Mesh tool (the one using gmsh) . On the mesh window, click Apply to mesh. Click OK to close.
5. In Edit/Preferences/FEA/General, I ticked 'Beside .FCStd file, so I can see my mesh saved at d:/cfdtest/aFace/FEMMeshGmsh. It is called Shape_mesh.UNV. I could convert it to Elmer's mesh format with Elmergrid.exe under win 10. the command in terminal is

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elmergrid 8 2 Shape_mesh.UNV

The Shape_Geometry.brep file is what I draw in FreeCAD. The shape2mesh.geo file is how to mesh in gmsh. Change these two lines

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// save
Mesh.Format = 2;
// Ignore Physical definitions and save all elements;
Mesh.SaveAll = 1;
Save "D:/CFDtest/aFace\FEMMeshGmsh\Shape_Mesh.unv";

to

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// save
Mesh.Format = 1;
// Ignore Physical definitions and save all elements;
Mesh.SaveAll = 1;
Save "D:/CFDtest/aFace\FEMMeshGmsh\Shape_Mesh.msh";

Then double click shape2mesh.geo in the folder, gmsh will generate a Shape_mesh.msh file. This file could be viewed by gmsh by double click. I could also convert it to Elmer's mesh format with Elmergrid.exe under win 10. the command in terminal now is

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elmergrid 14 2 Shape_mesh.msh

At the moment, I have problem to convert both UNV and msh. Convert UNV needs a new developer version of elmergrid.exe. Maybe need to add boundary condition.

Regards,

John

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from FreeCAD import Base
import Part

V1=Base.Vector(0,0,0)
V2=Base.Vector(300,0,0)
V3=Base.Vector(150,150,0)

L1=Part.LineSegment(V1,V2)
L2=Part.LineSegment(V2,V3)
L3=Part.LineSegment(V3,V1)

S=Part.Shape([L1,L2,L3])
W=Part.Wire(S.Edges)

F=Part.Face(W)
Part.show(F)

[RatonLaveur]

I have trouble understanding what you are trying to achieve. 2D Elmer cases can already be run all the way from FreeCAD GUI.

[johnwang]

In shape2mesh.geo, change these two lines as:

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// save
Mesh.Format = 'su2';
// Ignore Physical definitions and save all elements;
Mesh.SaveAll = 1;
Save "D:/CFDtest/aFace\FEMMeshGmsh\Shape_Mesh.su2";

I got su2 mesh. Will try to add BCs.

Edit:

It is generated by Mod\Fem\femmesh.py

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