[hapsari devi]

I am a beginner in using CFD Fluent, and when I am trying to check my mesh in fluent, it said that :
WARNING : unassigned interface zone detected for interface 6
WARNING : unassigned interface zone detected for interface 7
WARNING : unassigned interface zone detected for interface 11
would you please explain it for my why is it happen and how to solve it?

[-mAx-]

The reason is, you defined interface in Gambit (or another mesher), but you didn't set them in fluent (define/grid-interfaces)

[vasava]

In my opinion these errors are perfectly normal especially if you are simulating a case with interfaces.

The boundaries in two separate domains share one interface. Now these boundaries can not be declared as any other type (e.g. wall, inlet, outlet etc). If you declare them as e.g. wall then they can not be part of the interface. Thus when you bring your mesh to fluent it notices that you have not declared the type of boundary, and simply warns you about it.

So there is nothing wrong with the 'warning'. However you must ensure that the interface is properly set-up during meshing as well as in fluent.

[oj.bulmer]

Just make sure you avoid any words like zone, surface, interface etc. while defining any surface in meshing program. FLUENT grabs these words and assigns the boundary conditions to it, though often you dont want it to.

OJ

[viralnagar5692]

my dear but taking the wall as in interface solution is not initialized fluent.[/QUOTE]

[viralnagar5692]

Originally Posted by vasava

In my opinion these errors are perfectly normal especially if you are simulating a case with interfaces.

The boundaries in two separate domains share one interface. Now these boundaries can not be declared as any other type (e.g. wall, inlet, outlet etc). If you declare them as e.g. wall then they can not be part of the interface. Thus when you bring your mesh to fluent it notices that you have not declared the type of boundary, and simply warns you about it.

So there is nothing wrong with the 'warning'. However you must ensure that the interface is properly set-up during meshing as well as in fluent.

my dear frend,but i am facing the same problem in fluent and my solution is not initialized then how can i move ahead??
i have mentioned in mesh under named selction tool and also taken as interface in fluent
when i m going to initialize,error shows like-"Int. Flow-unassigned interface zone"
help me....

[R4RAHUL]

same problem here, but when I change the interface zone to wall then it calculate the solution but when I assign it as a interface zone then it shows error why is it so???????
I want to do it as a interface zone.

[ghost82]

Post some pictures of your interfaces.

[R4RAHUL]

I am attaching the Image of my geometry.
the green part shown in geometry, causing the interference problem, there is a upper surface and a lower surface both when assigned interference shows error.

[amr2006]

Hi all,

I faced the same problem and I overcome it by changing the boundary condition type to be (symmetry) and it worked for me as I am using a cylinder. I am not sure if having symmetry will be logic for your geometry but I guess (after I saw your geometry) it is a valid assumption

Amr,

[didane]

You may need to go to Mesh interface in FLUENT and create the interface by yourself might solve your problem...in case if it did not work go to MESH and suppress the contacts under connections.

[sepi_705]

Hi all

I am also facing a similar problem. I got that error message when I tried to initialize my solution in Fluent.
My geometry is a simple cylinder with a fluid domain around it. I want to show the flow of air (and dust particles) over and into my cylinder, so I defined the outer area of my cylinder as 'wall' and called the top surface of my cylinder 'interface' so Fluent would recognize it as an interior. I subtracted my cylinder from my fluid domain to do the meshing.

Please help me! I am very confused

(here's a link to what I've managed so far if anyone wants to take a look: https://drive.google.com/open?id=0B9...jJxS09qaURraE0)

[pakk]

Originally Posted by sepi_705

..and called the top surface of my cylinder 'interface' so Fluent would recognize it as an interior. ...

First of all: interior and interface are two different things. That is why they are also two different words.

Interface means, for Fluent at least, that it is a 'border' between two things. Graphically:

+--------------+
|              |
|    Zone A    |
|              |
+--Interface1--+
+--Interface2--+
|              |
|    Zone B    |
|              |
+--------------+

Interface1 is the boundary of zone A, and Interface2 is the boundary of zone B. In Fluent, you need to tell Fluent that Interface1 and Interface2 'touch' each other. After you have done that, both interfaces are 'assigned', and zones A and B are connected to each other.

If you don't tell Fluent that an interface is connected, it is unassigned. And Fluent will have a problem. If you make them walls, or symmetry, or something else, Fluent will not complain anymore that there are unassigned interfaces, but zones A and B will not be connected.


It looks like you (sepi_705) did the following:

+--------------+
|              |
|    Zone A    |
|              |
+--Interface1--+

You have one interface in your system. That does not make any sense for Fluent, Fluent does not understand what you want. An interface should always be assigned to a different interface, so you can not have 1 interface in your system.
And, not only Fluent is confused. I am also confused. Why are you making a system with one interface???

[sepi_705]

Originally Posted by pakk

First of all: interior and interface are two different things. That is why they are also two different words.

Interface means, for Fluent at least, that it is a 'border' between two things. Graphically:

+--------------+
|              |
|    Zone A    |
|              |
+--Interface1--+
+--Interface2--+
|              |
|    Zone B    |
|              |
+--------------+

Interface1 is the boundary of zone A, and Interface2 is the boundary of zone B. In Fluent, you need to tell Fluent that Interface1 and Interface2 'touch' each other. After you have done that, both interfaces are 'assigned', and zones A and B are connected to each other.

If you don't tell Fluent that an interface is connected, it is unassigned. And Fluent will have a problem. If you make them walls, or symmetry, or something else, Fluent will not complain anymore that there are unassigned interfaces, but zones A and B will not be connected.


It looks like you (sepi_705) did the following:

+--------------+
|              |
|    Zone A    |
|              |
+--Interface1--+

You have one interface in your system. That does not make any sense for Fluent, Fluent does not understand what you want. An interface should always be assigned to a different interface, so you can not have 1 interface in your system.
And, not only Fluent is confused. I am also confused. Why are you making a system with one interface???

Hi

I understand what you are saying, and I think that I may have names the faces incorrectly, but I think that I now have a situation where I have two different interfaces as shown in the image above, with the fluid in the cylinder and the fluid in the domain being separate.
Do I have to connect these two interfaces to get flow both within my fluid domain and cylinder?
If so, how do I achieve this?

I have uploaded a document showing some of the images I generated.
https://drive.google.com/open?id=0B9...FAyTldZYmFRMzA

Thank you for the help

[Roya.TR]

dear pakk
i have this problem too,
how acn i trell to fluent that interfaces touch each other?

[pakk]

Give the two interfaces the type "interface".
Select the menu "Create/Edit Mesh Interfaces".
For "Interface Zones Side 1", select one side, for "Interface Zones Side 2" the other side.

[Shreman]

Thanks..I solved unassigned interface error changing a name from "interface" to some other like ¨intfr¨ .It worked.Merci

[pakk]

I assume you did that in the mesher, because if you did it in Fluent it makes no sense.

What happened then was that Fluent made this a wall. Your liquid will not go this surface anymore.

If you really wanted the surface to be an interface (such that liquid can go through), you did not solve the problem. You simply got rid of the error message.

[sivakumar]

Hi All,
I am working on the finned tube heat ex-changer, I just followed the tutorial in the youtube.

I am using Gambit for pre-processing and I have defined the BC's there itself.

Defined the Zones as hotFluid, coldFluid and tube.

The fins thickness is 3 mm, the inner cylinder and fins I consider as tube. The hot fluid and cold fluid are separated by the tube (cylinder with fins)

I have problem with the interfaces between hot fluid and cold fluid, I have defined tube inner as interface1, tube outer as interface2.

I exported the mesh to fluent, while checking the mesh I am getting the following error.

Checking mesh............... Error: interface zone 6 has two adjacent cell zones.


Error: interface zone 7 has two adjacent cell zones.
.........
WARNING: Unassigned interface zone detected for interface 6
WARNING: Unassigned interface zone detected for interface 7............
Done.


WARNING: Mesh check failed.


Error: interface zone 6 has two adjacent cell zones.


Error: interface zone 7 has two adjacent cell zones.


Error: interface zone 6 has two adjacent cell zones.


Error: interface zone 7 has two adjacent cell zones.


Error: interface zone 6 has two adjacent cell zones.


Error: interface zone 7 has two adjacent cell zones.


I tried to define the interface in the mesh interface section but no success. I couldn't see any connected faces.


Please help me to fix the issue.


Thanks in advance,


Sivakumar

[-mAx-]

You need to define the interface in Gambit (you did it), and then you need to assign the "coupling" in fluent.
Once this last point will be achieved in fluent, the check mesh will be sucessfull.
According to your picture, the tube_inner and tube_outer interfaces should be exactly the same surfaces, except one belongs to cold fluid domain, and the other to the hot one..