Different of union, split, and subtract
 

Excuse me,
Hello everybody, I need your help about drawing geometry.
Which one the better of union,split, or subtract to make one geometry which has two volumes or zones and connected each other ?
Thank you.

it depends on your geometries
display them and tell how you want to mesh them

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I want mesh them with different mesh, but I want they are connected each other. Thank you

no facebook access from office

Iam sorry.
How to upload image without facebook link ?
Thank you.

by clicking on "Go Advanced" you have more possibilities for editing (attachment for example)

Attachment 28751

This is my geometry, thank you.

Is volume 2 a solid or a fluid domain?

volume 2 is a fluid domain.

do you have someting between volume 1 and 2?
Is volume 2 included in volume 1?

Yes, between volume 1 and volume 2, there is porous media.

then you need a third volume for modeling this porous zone
your fluid flows through volume 1 , then porous, then volume 2

oh, thank you.
Where is the position of third volume ?

between both volumes, but that should you know (don't you have a cad sketch or whatever?)

Ok, thank you
Which one the better of union,split, or subtract when I finished three volume to connected them ?

if "contact" surfaces match them together you only have to connect faces. It means Gambit will connect "contact" face from volume 1 with "contact" face from volume 2 and will merge both surfaces. Finally you will have a common face betwenn volume 1 and volume 2.
But it will only work if both contact surfaces are exactly the same.
Did you build the geometry in Gambit or from cad package?

Yes, I build the geometry in Gambit.
I hope it works.

did you build your geometry from a paper? if yes, can you display it?

Yes, I will display it.

has your porous zone 0-thickness?