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-   -   POROUS MEDIA (http://www.cfd-online.com/Forums/fluent/40443-porous-media.html)

Sean Cody April 4, 2006 15:49

POROUS MEDIA
 
Trying to simulate porous media (screen over a pipe inlet). I specify porous jump in gambit for face i want to be porous media but when importing mesh to fluent it says it cannot be porous because "there is only one adjacent cell thread"...also mentions that it is an inappropriate zone type for one sided face...how do i make a double sided face? Any help would be great.

Sean

Ralf Schmidt April 5, 2006 02:59

Re: POROUS MEDIA
 
When creating the geometry, take a good care, that the face is connected to BOTH volumes!!!

Sometimes it happens, that there are two volumes touching each other but are not connected. The faces may have the same positions, but are not the same.

"how do i make a double sided face?" - Try to use the "connect" button - it looks like a plug. That can connect the faces from both volumes that touch each other.

Ralf

spepsicho April 5, 2006 06:18

Re: POROUS MEDIA
 
there is a big difference between porous media et porous jump: porous media must be a fluid type zone (with 3D cells) whereas porous jump is just un 0-thickness face, like interior or radiator.

maybe that's your problem...

Ernest Bertrand April 5, 2006 08:08

Re: POROUS MEDIA
 
If you trying to model a screen over a pipe inlet, you probably need an "inlet vent".

Marijo April 5, 2006 18:22

Re: POROUS MEDIA
 
If you have 2d model do this: - for porous jump you need two faces where porous jump is a line between the two faces,specify this line to be porous jump in GAMBIT - for porous media you have to create a face which will be the screen.Then specify that face to be fluid zone in GAMBIT, and in Fluent you'll specify to be porous zone.

If you have 3D model let me know and I'll write you back.

Marijo

fadiga May 4, 2012 09:40

Re: Porous Media
 
1 Attachment(s)
I know this thread is rather old...but am having difficulty also understanding the porous jump - at least this is what I believe I need...I am trying to simulate flow through a wind tunnel test section which has a partially inserted wire screen in it. I am at the moment simplifying to a 2D model, so I have something that looks like this (see attached scrnshot, flow right to left).

My problem is also with meshing and specifiying the BC...I tried modelling the screen as a very thin face (so i gave it a thickness in Gambit of 1mm) -here I had problems when meshing, the faces were not connected properly, I also then tried connecting them, but failed aswell...

I feel I am missing out on a rly simple fix and idea...Can anyone enlighten?

Thanks alot!!

fadiga May 4, 2012 09:45

Btw, in the screenshot I posted, the red line at the lower right corner is actually the very thin face representing the screen....
Thanks!

kitrax May 14, 2012 09:23

Hi Fadiga, try heal your faces, that might allow the model to work properly...I am not the most experienced gambit user though so might be wrong

Leram March 6, 2013 11:33

Quote:

Originally Posted by Marijo
;130996
If you have 2d model do this: - for porous jump you need two faces where porous jump is a line between the two faces,specify this line to be porous jump in GAMBIT - for porous media you have to create a face which will be the screen.Then specify that face to be fluid zone in GAMBIT, and in Fluent you'll specify to be porous zone.

If you have 3D model let me know and I'll write you back.

Marijo

I am modelling a tube through which mixture of air and water passes and there is an air permeable membrane around the internal wall of the tube which is permeable to air only. I should model this as VOF in Fluent.

First, I need to set this wall boundary as Porous Jump in Gambit. I did the following steps in Gambit and when importing the mesh into Fluent, I got the Error Message : "Cannot change porous to porous-jump because there is only one adjacent cell thread".

1) created a cylinder as volume
2) meshed it
3) set the boundaries as inflow, outflow, and porous jump (for the face around the cylinder)
4) set one fluid zone for the entire volume
5) export the mesh to Fluent

I was wondering if you could help me define this problem? Much appriciated!

Thanks,
Leram


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