How to identify zones in a Mesh

[N. M.]

Hello Everyone,

I am working with Fluent on a multibody geometry. During the meshing process, I manually create the connections between all the bodies because the automatic connection generation does not capture all of them.

When I run the simulation in Fluent, it starts, but the software displays the following message:

Info: Interface zones, 8 and 9, possibly penetrate each other. This could adversely affect your solution.

I suspect that this issue is affecting my results.

How can I locate the referenced zones 8 and 9 in the mesh?

Thank you! 😀

[N. M.]

UPDATE:

Through online research, I found the command:
/def/bc/zone-name (zone number)
which allows identifying the zone name from the given ID.

The zones in question are ”bonded_-_ambient_to_ambient-src” and ”bonded_-_ambient_to_ambient-trg,” as shown in the attached figure. These two zones represent the interfaces of all the manual connections I created in Meshing.

So, the previously mentioned message:
Info: Interface zones, 8 and 9, possibly penetrate each other. This could adversely affect your solution.

could be a critical issue for my simulation?
If so, how can I resolve it?

Thank you! 😀

 

 

[Rob]

Share topology didn't work?  Interface zones can't penetrate like that, and ideally, you'd just have interiors. It's fixable in Fluent, but only by breaking up the interface zones and then manually pairing faces: assuming there aren't any other issues that aren't visible. 

[N. M.]

Using "Share Topology", I encounter other errors (see attached figure).

 

[Rob]

What did you do the Share Topo operation in?

[N. M.]

Geometry.
My geometry is a multybody geometry, each single body of which has been created with a Sweep command (attached figure).

 

[Rob]

Ah, you need a multibody part. That should do Share Topo automatically and you should then have a conformal mesh. If any of the faces need to be thin walls use a Named Selection in Meshing (eg wall-baffle and wall-another-baffle). If that fails check you are linking the sketches together so the points & edges are shared by the neighbouring one. 

[N. M.]

 

I created a Part containing all the single bodies and use the Share Topology.
It gives me a warning (attached figure)

Is it a problem?

 

 

[Rob]

You shouldn't need Share Topo with a multibody part. It's likely just connecting faces together and possibly merging nodes, so should be fine. Mesh it and see what happens. 

[N. M.]

Ok, I tried creating a single Part without using Share Topology. However, when I open Meshing, one body is missing (see attached figure). I don’t understand why—it's neither hidden nor suppressed.

[Rob]

Do you just have volumes in DM or are there some faces? How many volumes have you got?

[N. M.]

 

In the Geometry, I have 159 fluid bodies, all created through sweeping.
I tried redrawing the geometry from scratch and followed your suggestion to merge everything into a single Part. However, when I transition to Meshing, the problem persists.

In addition to some bodies being removed (Figure 1), it also appears that a slicing operation has split existing bodies (Figure 2), even though I did not perform any such operation while creating the geometry (this automatic slice seems to follow a circular trajectory of an arch I use in a sketch).

Upon opening Meshing, the following warnings appear (Figures 3 and 4).

 

 

 

 

 

[Rob]

Is that built with one sketch per volume? Or some larger sketches and then splits? 

[N. M.]

I created this sketch on the XY plane and then swept each closed shape (each closed loop of four edges) using the Sweep command in both perpendicular directions of the XY plane, following a drawn path.

 

[Rob]

And that's a single sketch? As opposed to 45-ish sketches? 

[N. M.]

Yes, it is a single sketch.

[Rob]

Ah, connected closed loops can cause problems, and that may explain the missing volumes. A safer option is to create a sketch of the overall shape and then some sketches to slice the domain. A sketch can comprise multiple disconnected lines that are then swept (zero thickness) too. 

I don't think there is much public learning content for DM as it was replaced by SpaceClaim and Discovery before the AIS materials were created. 

[N. M.]

So, a possible approach could be to draw both the inner and outer parts of the shape in a single sketch, then sweep it to create the overall domain as a single body. Next, draw all the internal edges in a separate sketch and use them to slice the original domain into a series of smaller bodies?

[Rob]

I'd generate "outer" then add "inner" using subtract. That gets you the main volume. Then some sketches to slice the rest of the zone up.