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-   -   create Volume with inlets (http://www.cfd-online.com/Forums/fluent/27397-create-volume-inlets.html)

Roman Bohnes December 3, 1999 03:58

create Volume with inlets
 
I have a problem in creating a boiler with air inlets in the wall. Actuall I have build up the walls and the air inlets, both are faces. Now I try to build up a volume, with the faces and the wall, but fluent told me that the inlets aren*t meshed. How can I connect the inlets or include them in the calculation?

best regards

roman

Allan Thomson December 3, 1999 07:06

Re: create Volume with inlets
 
What pre-processor package are you using?

Roman Bohnes December 3, 1999 09:09

Re: create Volume with inlets
 
gambit

Jonas Larsson December 3, 1999 10:08

Re: create Volume with inlets
 
Not sure about what you are trying to do. Do you have a geometrical volume that you are trying to volume mesh, or are you trying to create a geometrical volume?

Roman Bohnes December 3, 1999 10:31

Re: create Volume with inlets
 
I have a wall, with holes in it. These holes are air inlets. I tried to create both as faces and then separate them. But that wasn't succesful. Gambit didn't combine the mesh of the faces with the volume mesh. So I haven't any boundary conditions for them and all that stuff, what goes with it. Is that clear?

Jonas Larsson December 3, 1999 14:50

Re: create Volume with inlets
 
Hmm, sounds like you're doing things in the wrong order. With Gambit you must first create a geometriacal volume. You do this by "stiching" faces (or by directly creating a 3D volume like a cylinder, brick, ...). When you have this volume finished you then start meshing it - you can try to mesh it as a volume directly or you can start by meshing edges and then faces first (gives you more control). Then, when you are finished with the mesh, you define which faces that should be inlets, outlets etc. I hope I'm answering the right question here.

reyman December 3, 1999 15:03

Re: create Volume with inlets
 
Roman you may try by rebuilding your 'primary' volume, then placing cylinders of diameter desired for your holes in exactly the location where you want the holes to be. Then "Split" -with bidirectional split invoked- the primary volume with the cylinders. You should have three volumes now (if only one cylinder is split through the wall) since the cylinder will be split into two pieces. Boolean unite the portion of the cylinder inside with the primary volume around it. Then delete the remaining portion of the cylinder that lies outside. You should now have only a face (a hole) remaining in the wall of the primary volume. Since you conducted the "splitting" operation, the edges of the "hole" will also be shared by the wall of the primary volume and meshing will be consistent.

Now mesh the "holes" (I do quad pave but there is also tri pave if you prefer), then face mesh the remaining portion of the wall. If your geometry is simple, you will be able to cooper the quad elements through the rest of the volume resulting in a nice hexahedral mesh. If your geometry is not simple, you may wish to leave the cylinders in the primary volume but split from the rest of the volume. This will allow nice meshing later. If your solution will be determined from Fluent, the default for interior volume meshes is to consider them parts of the same fluid, however if you're solving in Fidap, you will need to define the internal volumes as 'attached' (ATTA) and 'not attached' (NATT) faces to the volume surrounding the cylinders in order to maintain the fluid's consistency.

I think this information can also be found in the respective manuals.

-reyman

Sandeep Abhyankar December 3, 1999 15:04

Re: create Volume with inlets
 
I think the way to go would be to create the volume first, then on one of the wall face where you have to put your air inlets..draw faces corresponding to your inlets , then split the wall face with the each air inlet faces. Then mesh the whole vol. Should work this way.!

wang haigang December 4, 1999 22:46

Re: create Volume with inlets
 
Hi, I think you should first generate the mesh in Gambit then read the mesh file to Fluent 5.0 or high version,split the face into two part or more.I offen use this metod in my simulation. Regards, wang haigang

Jean-Yves December 5, 1999 10:15

Re: create Volume with inlets
 
I think the previous message is right. We did a boiler and you have to create the volume. Create the faces. Then split the faces. So you volume is made of all you faces. Then mesh each faces. Finally mesh the volume. Give a name and attribute to your inlet faces: velocity inlet... import the mesh to fluent.

jy http://www.pfd.ie

Roman Bohnes December 6, 1999 05:43

thanx!
 
Your information was very helpful to me!


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