[nik.ferg]

Hi everyone,

I have a problem and I don't know how to fix it.

I have a fluid entering a circular tube and exiting on the other side. Inside the tube I put inserts to see if this has an effect on turbulence ect.

When I try to run CFX-solver it breaks down before it starts.

It says: "isolated fluid regions were found in domain Default Domain"

I read somewhere that a solution could be to set the expert parameter "check isolated regions = f".

I tried this and although the solver worked, it isn't a correct streamline in CFX-Post.

I attached a photo so you can see what I mean.

Does anyone know what to do?
I would be extremely grateful.

Nik

Problem.PNG

[highorder_cfd]

I think you are basically getting somewhere 2 separated domains and there is no interface linking them. So you have 2 separated fluid regions.

1) Remove the expert parameter.
2) Try to understand why CFX is identifying two separate fluid domains

[nik.ferg]

Thanks highorder_cfd!

I tried the first step you mentioned and CFX-Solver just breaks down before the first iteration.

As for step 2. That is exactly the part I do not understand. Do you have any suggestions on how to fix it?

Thank you !

[highorder_cfd]

There is something basically wrong in your domains definition.

When you setup your default fluid domain in CFX, in the Basics Settings tab>Location and Type>Location> expand [...] and here you will display all the meshing parts which will be showed in the view window, so you can undestand if actually there is a separate fluid region in your case.

Originally Posted by nik.ferg

Thanks highorder_cfd!

I tried the first step you mentioned and CFX-Solver just breaks down before the first iteration.

As for step 2. That is exactly the part I do not understand. Do you have any suggestions on how to fix it?

Thank you !

[mo-ca]

Originally Posted by nik.ferg

When I try to run CFX-solver it breaks down before it starts.
It says: "isolated fluid regions were found in domain Default Domain"

Originally Posted by highorder_cfd

I think you are basically getting somewhere 2 separated domains and there is no interface linking them. So you have 2 separated fluid regions.

1) Remove the expert parameter.
2) Try to understand why CFX is identifying two separate fluid domains

by using this expert parameter, you are basically disabling the check, not solving the problem. As stated before: your domains are not connected, so the fluid cannot pass right through. This is why your streamlines look odd. Did you deactivate the automatic interface creation? There should be an interface connecting each domain with the next one, enabling fluid and heat exchange.

[nik.ferg]

Thank you very much for your reply.

Can you tell me where I can check if the automatic interface creation is activated or not?

Thanks a lot!

[nik.ferg]

I found out where to check the setting. It was activated. I deactivated it and it would complete "normally" before completing the first iteration and it did not produce results.

[zacko]

Is it an option to make a Fluid Domain and than a Solid Domain with the inner parts? Then maybe a few interfaces of Fluid/Solid...

CFX will usually create automatic interfaces so u can delete them If u think they are wrong and than create your domains with the interfaces