[Ema40]

Hello,

I have used until now Fluent, but now I want to use Open Foam.

My question is this. In Fluent it is possible to design the geometry in Autocad and import the geometry file into Ansys and mesh it, by clicking on the bodies and surfaces. Therefore, the bodies and surfaces can be of whatever shape.
But in Open Foam? I can not click on the bodies and surfaces to say to the mesher that in that body or surface I want a particular mesh. If the body is simple (a parallelepiped for example), it can be defined by its vertex. But a very complex and irregular shape?

Thank you very much

[pbalz]

Hi Ema,

snappyHexMesh is the tool you're looking for.
Just have a look at the tutorials to get a feeling about what it is capable of... and what not. For most cases it will create nice (hex dominant) meshes but you need to learn how the parameters of snappy influence the resulting mesh.
In general you don't have a GUI for meshing here... Just a text file.

Another possibility is to create the mesh in Ansys and then export it into OpenFoam (with fluent3DMeshToFoam).

[Ema40]

Thank you.

My problem would be how to deal with complex shapes. It will be difficult, without a GUI, to define a complex and irregular surface or body in Open Foam, using only a text code.

I could import the geometry from Autocad, but how can I identify a particular surface in Open Foam, after that I have imported the geometry from Autocad? In Ansys it is simple because you can select it by clicking on it, but in open Foam? When you import a geometry file, is Open Foam able from itself to decompose the total geometry in bodies and surfaces? If yes, you can look at the coordinates of each surface, understand what surface/body refers to, and give to it a name or a boundary condition. But can Open Foam do this decomposition?

When I export the mesh from Fluent to Open Foam, also the name of each surface (that I define in Ansys mesher) will be exported? The problem in Open Foam also is the definition of the boundary conditions on each surface, so if each surface has the proper name (defined in Ansys mesher) it will be simpler in Open Foam to define the Boundary Conditions.

Thank you!!
Regards

[akidess]

You name your surfaces and parts in Autocad, and export to STLs (either multiple, or a single with multiple solids). Then it's not problem to identify the geometry in OpenFoam, and mesh accordingly with snappyHexMesh. And yes, if you export the mesh from Ansys the names should be preserved.

[Ema40]

Thank you very much!!!!