[mech_sim]

Hi,
can anybody tell me how I can change zone type of some cells with udf in fluent?
Thank you

[pakk]

I don't think that is possible with a udf.

[znri]

Thank you Pakk. Instead of that, can I import two .msh files to fluent and then replace the zone of some cells with udf?
Best ragards

[CeesH]

Why would you want that?

[znri]

I have a .msh file for a foam like structure, with solid and fluid zones. I only need a central sphere of that cube, whereas the outside of sphere be in fluid zones.

[CeesH]

Why do you need to specify that in FLUENT? Can't you divide the geometry in the desired zones in the geometry or meshing step?

[pakk]

I can see two ways to do this.

1. As CeesH says: don't do this in Fluent, but do this before you make your mesh. This is by far the easiest method.
2. If, for some reason, you only have the .msh files and you can not get access to the original geometry, there is a workaround. Move the geometry (by translate mesh) such that the center of the sphere is in the origin, define a custom field function as the distance to the origin, and mark (adapt->mark) cells with that custom field function smaller than the radius, and then separate your mesh (mesh->separate) with "marked". You will have to sort some of the details out yourself, and the result will not be a smooth sphere because it will follow the mesh faces in your original mesh. I would strongly advice against this.

But in your questions you keep saying you want to do it with a udf. Is there a reason why you want a udf for this? I don't see any reason for that.

[znri]

Thank you for your reply. Actually I only have the .msh file. And as you mentioned, in this way I will haven't a smooth sphere. But it's the only way. I did the procedure you proposed, before. As I mentioned before, my msh file is contained of solid and fluid zones. When I separated the marked region (outside of the sphere), the solid zone divided to two region. Then I tried to merge the outside of the sphere with the fluid zone. But it didn't work. In the opened window (mesh->merge), I only could merge regions with the same type of zone. Can you please tell me how can I merge the regions?
The reason for using udf is that I haven't a way to merge the regions (with different zone types) in my mind. Let me know what is your suggestion?
Best regards

[pakk]

Originally Posted by znri

Thank you for your reply. Actually I only have the .msh file. And as you mentioned, in this way I will haven't a smooth sphere. But it's the only way. I did the procedure you proposed, before. As I mentioned before, my msh file is contained of solid and fluid zones. When I separated the marked region (outside of the sphere), the solid zone divided to two region.

Fine until here.

Then I tried to merge the outside of the sphere with the fluid zone.

Why would you try that? That does not help you to obtain what you want...

What you want is to make the outside of the sphere fluid. So do that. Go to "Cell Zone Conditions", select the zone you want to change, and change "Type" from "Solid" to "Fluid". If you want, you could merge afterwards, but merging is not the answer to your problem.

[znri]

Thank you for your helpful reply. Now how can I export mesh file with new zones from fluent? I would like to import it to ICEM.
Best regards

[pakk]

As far as I know, that is impossible to do with Fluent. I would not know how. If you manage to do this, please let me know!

[ket1]

can an one help me out in explaining : what is meant by mesh orientation in north and east in solar radiaton model. what does 0 and 1 signify