[Gmsh] Problem meshing a sphere. gmsh crash meshing or not recognize the volume.

Hugo Fernando Maia Milan hugomaiamilan at hotmail.com
Wed Sep 24 14:00:21 CEST 2014


I didn't unterstand your question. What do you mean by "volume of the sphere without mesh"? If you are simply using my code, you can get the volume by the radius in the file. As you can see in the code, "raio" is the radius of the sphere.


Date: Tue, 23 Sep 2014 23:32:43 -0500
Subject: Re: [Gmsh] Problem meshing a sphere. gmsh crash meshing or not recognize the volume.
From: vb.esteban at gmail.com
To: hugomaiamilan at hotmail.com
CC: gmsh-request at geuz.org; gmsh at geuz.org

Thanks hugo. 
That works nice and finally can get the mesh.
But, how do I proceed to get the volume of the sphere with no mesh? It's possible? 
2014-09-23 8:00 GMT-05:00 Hugo Fernando Maia Milan <hugomaiamilan at hotmail.com>:


It looks that the size of the point that you defined are very small compared to the size of the object. I had created a new file, check it in the attached.

In this file, you can specify the radius of the sphere and the lengths of the rectangle. Pay attention in the size of the points because they are critical in regard of the size of your elements (and the mesh, consequently).

If it is too slow or you can't create the mesh, just increase the values of lc and lesfera in the file.


Date: Mon, 22 Sep 2014 10:28:20 -0500
From: vb.esteban at gmail.com
To: gmsh-request at geuz.org; gmsh at geuz.org
Subject: [Gmsh] Problem meshing a sphere. gmsh crash meshing or not	recognize the volume.


I'm a new user of gmsh, I have developed some tutorials in it, but now i have several problemas.

I'm trying to simulate the flow around a sphere, the main goal is calculate the drag force and drag coefficient in OpenFOAM. However, I'm having a lot of problems creating the mesh, I've made two process to generate the mesh with no success at all.

First way.
1. I generate a CAD model in solidEDGE, in that model I draw a solid volume with the hole of the sphere (boolean operation). The volume represent the all fluid.
2. I export the CAD Model into step, stl and igs files.
3. In gmsh, merge the step model.
4. gmsh show the surfaces, points and volumes rigth (gmsh show the walls in gray solid color).
5. Define the physical groups, surfaces with no problem.
6. When I try to select the volume in physical group is just impossible.

Second Way
As the geometry is a bit simple, I decided to draw the sphere and the box in which its embeded in gmsh.

1. I draw some points to define the sphere.
2. Create circle arc to define the sphere.
3. With those circle arcs created I defined ruled surface in the sphere.
4. Then Create the box around the sphere.
5. The surfaces in physical groups are defined normally, but I created a surface call sphere, in which I select the all ruled surfaces created on the sphere.
7. Then, with everything O.K. I try to create the mesh, but the program just crash, and close.

I have a problem to open gmsh to, everytime I try to open it I have to write in the console (Ubuntu) this: gmsh primary.geo -tol 1e-9

I attach the geo file.

Thanks! I really appreciate any comment about it.

spheredesarrollada.geo is the second way file generated.
sphereNueva.geo is the first way file
Esteban Vargas BolívarMetálicas Léguz S.A.Tel.: (4)5203600 Ext. 103

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Esteban Vargas BolívarMetálicas Léguz S.A.Tel.: (4)5203600 Ext. 103
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