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-   -   Problem with Domain Interfaces (http://www.cfd-online.com/Forums/cfx/22506-problem-domain-interfaces.html)

hagupta April 30, 2006 08:36

Problem with Domain Interfaces
 
I have meshed separately, a cylinder and a pipe that is to be joined to it in ICEM CFD. After importing the 2 meshes to CFX, I cannot find the part name of the surface to be interfaced, in one of my mesh. So I am unable to proceed.

Where could I have possible made a mistake? Any suggestions are welcome.

hagupta May 1, 2006 09:39

Loading .msh file to CFX
 
I think I should reframe my question as follows

I have loaded a mesh file (made in ICEM CFD) to CFX Pre. In ICEM, several part names had been assigned (to the geometry to use them as BC or surface for Domain Interface in CFX Pre). However, I find that some of these part names(of few surfaces) cannot be seen in CFX Pre.

What are the requirements for to ensure all part names are visible in CFX Pre?

jemteo May 1, 2006 13:48

Re: Loading .msh file to CFX
 
after the mesh is loaded...go to the TAB..REGION to see if your partnames are there. sometimes the partname will not be in the pulldown list..might be in the extended list (button next to the pulldown list)

hagupta May 1, 2006 14:33

Re: Loading .msh file to CFX
 
Thanks for the reply, jemteo. I have checked the extended list and they cannot be seen even there.


Flok May 1, 2006 15:17

Re: Loading .msh file to CFX
 
A .msh is for fluent, should you read this in fluent?

hagupta May 1, 2006 23:16

Re: Loading .msh file to CFX
 
Even CFX accepts .msh format.

svr May 2, 2006 00:31

Re: Loading .msh file to CFX
 
hi hagupta, I hope you named the surface after meshing the domine. this may create problem some times.name the parts before meshing. This may solve your problem

hagupta May 3, 2006 10:21

Re: Loading .msh file to CFX
 
Thanks for the reply. I had named the parts before meshing.

But, I have used hex mesh. In hex, I think all parts have to be in some way associated with the blocking. The parts whose names cannot be seen, are those who had nothing to do with blocking.

Can anyone knowing hex meshing help me out?

TB May 4, 2006 01:09

Re: Loading .msh file to CFX
 
1.check if you select ANSYS CFX when you export the mesh 2.check if you can load two meshes to PRE separately. If one mesh is not accepted, no point to try to combine them. 3.check if you have latest patches installed for ICEM. 4.check the mesh problem using option in "edit mesh" 5.try to define a different part name for the interface surface on these two meshes. 6.Have you converted it to unstructured meshes before you export it?

Forrest May 4, 2006 12:51

Re: Loading .msh file to CFX
 
hagupta,

I suppose your missing part names are those which are going to be used as domain interfaces later on. They should be defined as 'internal walls' before you mesh the 'body'. You can define the 'interal walls' under 'global mesh size'. You may also need to define multi-bodies first in order to set up multi-domains later in PRE, that's when you need to set domain intefaces.

Good luck, Forrest

hagupta May 5, 2006 11:29

Re: Loading .msh file to CFX
 
Thanks for you reply, forest.

Yes, the missing part names are those which are going to be used as domain interfaces later on.

And yes, I have also not defined these surfaces as 'internal walls' before meshing the 'body'. How do I define these surfaces as 'internal walls' before meshing?

>>You can define the 'interal walls' under 'global mesh size'. Are you talking about the 'global mesh size' in the 'Mesh'Tab ? I have used hex mesh and so all the meshing was done using the options in the 'Blocking' tab.

>>You may also need to define multi-bodies first in order to set up multi-domains later in PRE, that's when you need to set domain intefaces. I will not be using multi-domains, still do I need to define multi-bodies?

I am new to hex meshing, hence the above questions.

Forrest May 5, 2006 11:59

Re: Loading .msh file to CFX
 
1. The function of 'Mesh' tab is still available for use even you are using 'blocking'. For example, after you define your blocks, before you assign any number of nodes to your edges, you can set a surface mesh under the 'Mesh' tab, you can still mesh your geometry. So within your geometry, if there are 'internal walls', you need to set them under the 'global mesh size' tab.

2. Bit curious, if you don't use multi-domains, why do you need to set 'domain interfaces'? I thought 'domain interfaces' are used to connect different domains (fluid-fluid, solid-fluid, etc).

Good luck, Forrest


hagupta May 5, 2006 12:25

Re: Loading .msh file to CFX
 
Ok, thanks for the help, I think this should solve my mesh problem. I will try this when I go the next week.

Dividing my geometry into 2 parts and then hex meshing it makes it easier to mesh and also proper mesh parameters can be set for parts having different sizes.(my geometry consists of a main cylinder with some cylindrical nozzles meeting the cylindrical surface tangentially) So, although my simulations contains a single domain, i will use domain interface to join these parts as a fluid-fluid interface.


hagupta May 5, 2006 12:41

Re: Loading .msh file to CFX
 
Can you also tell me if "defining the surfaces as internal walls in global mesh parameters" will be sufficient or i will "need to define all the internal walls by the edges and then project the face(of the block) to the surface"

I do not know what exactly the statement in the second quote means and how do I do that, it was the solution given by CFX support. Will "defining the surfaces as internal walls in global mesh parameters" be sufficient?

Thanks, hagupta


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