fluid porous interface

NewGuy · March 11, 2015, 05:15

Dear all,

I am trying to model natural ventilation in a building. I would like the windows to be porous where I can control the amount of air entering from outside. I am not able to select a specific face to include in the default porous fluid interface as it stays in the default domain boundary as a wall.

could you please help me with this issue.?

Regards
Faraaz

monkey1 · March 11, 2015, 05:56

Hmm
1. Do you have different domains (a porous window domain and a fluid domain)? An Interface only exists between 2 separate Domains and meshes.
2. Why do the windows have to be porous? Why not just use an Inlet with a defined mass flow?

NewGuy · March 11, 2015, 13:06

Dear monkey1,
Thanks for your reply. I am actually modelling part of the external flow as well. That's why the porous interface to take into account louvres. I now know why I wasn't able to add faces to the default created porous fluid interface. I just had to create a new interface and add all the faces I wanted and voila, it's all good to go.
Thanks again for your reply. Any advise would greatly appreciated.

Faraaz

ghorrocks · March 11, 2015, 18:33

Rather than making them porous volumes you should make them interfaces and put a flow resistance on the interface. And yes, you will have to have these faces defined in the mesh. But it looks like you have worked this out yourself

NewGuy · March 12, 2015, 01:45

Thanks for the reply ghorrocks. I have 2 more simulations with different geometries to do. I now have a better idea of how to proceed. Thanks.

NewGuy · March 12, 2015, 02:13

Hi, I got 1 question. I had to pick one by one from hundreds of faces to add to the interface. This gets very time consuming. Is there any faster way of doing this. I had to identity all the faces first from the list on the left before adding to the interface.
Regards
Faraaz

monkey1 · March 12, 2015, 02:34

Didn't you name your parts when doing your mesh?
When meshing you can name all surfaces by specific names (e.g. Door, Wall, Floor, WEindow 1, Window 2, etc.). Then it is easier to find them in pre.
But you can also regroup several separate surfaces under one Part Name, e.g. if you have 10 windows on the left and 10 on the right, you can create one part "Windows Left" and selevt all 10 Windows on the left to be part of the group and the same for "Windows RIght". In Pre you would then only have to chose ONE part Name to acces 10 surfaces. BUT you should think about the Parts needed very carefully. Because if you suddenly need single suraces instead of the grouped ones, you are back to identifiying and selecting each surface one by one.

I hope thats what you wanted to know

NewGuy · March 12, 2015, 03:52

Hmm. Yes my geometry does consist of multibody parts named accordingly. It all shows up in mesh. However as you said I need 1 or 2 faces in a window or door in pre for example. In pre all the parts and their faces are numbered. So I have to pick one by one. I was just thinking whether there might be a better way to do this.
Thanks.

EvanGu · February 21, 2017, 00:04

Quote:

Originally Posted by ghorrocks

Rather than making them porous volumes you should make them interfaces and put a flow resistance on the interface. And yes, you will have to have these faces defined in the mesh. But it looks like you have worked this out yourself

ghorrocks, I want to define flow resistance on the interface for simulate perforate tiles used in CRAC air flow supply, can you tell me the steps for flow resistance define? thanks for your help.

best regards , Evan

March 11, 2015, 05:15	fluid porous interface	#1
NewGuy New Member Join Date: Nov 2010 Posts: 7 Rep Power: 16	Dear all, I am trying to model natural ventilation in a building. I would like the windows to be porous where I can control the amount of air entering from outside. I am not able to select a specific face to include in the default porous fluid interface as it stays in the default domain boundary as a wall. could you please help me with this issue.? Regards Faraaz

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
fluid porous domain interface	lauda	Main CFD Forum	0	July 31, 2014 10:29
GETVAR Error in Multiband Monte Carlo Radiation Simulation with Directional Source	silvan	CFX	3	June 16, 2014 10:49
Question about heat transfer coefficient setting for CFX	Anna Tian	CFX	1	June 16, 2013 07:28
Heat Flux at Internal walls or Fluid Solid Interface	Mahi	CFX	3	October 1, 2012 03:18
Y plus in fluid fluid interface	Subha	CFX	4	March 4, 2008 09:56

March 11, 2015, 05:56		#2
monkey1 Senior Member Join Date: Jul 2011 Location: Berlin, Germany Posts: 173 Rep Power: 15	Hmm 1. Do you have different domains (a porous window domain and a fluid domain)? An Interface only exists between 2 separate Domains and meshes. 2. Why do the windows have to be porous? Why not just use an Inlet with a defined mass flow?

March 11, 2015, 13:06		#3
NewGuy New Member Join Date: Nov 2010 Posts: 7 Rep Power: 16	Dear monkey1, Thanks for your reply. I am actually modelling part of the external flow as well. That's why the porous interface to take into account louvres. I now know why I wasn't able to add faces to the default created porous fluid interface. I just had to create a new interface and add all the faces I wanted and voila, it's all good to go. Thanks again for your reply. Any advise would greatly appreciated. Faraaz

March 11, 2015, 18:33		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	Rather than making them porous volumes you should make them interfaces and put a flow resistance on the interface. And yes, you will have to have these faces defined in the mesh. But it looks like you have worked this out yourself

March 12, 2015, 01:45		#5
NewGuy New Member Join Date: Nov 2010 Posts: 7 Rep Power: 16	Thanks for the reply ghorrocks. I have 2 more simulations with different geometries to do. I now have a better idea of how to proceed. Thanks.

March 12, 2015, 02:13		#6
NewGuy New Member Join Date: Nov 2010 Posts: 7 Rep Power: 16	Hi, I got 1 question. I had to pick one by one from hundreds of faces to add to the interface. This gets very time consuming. Is there any faster way of doing this. I had to identity all the faces first from the list on the left before adding to the interface. Regards Faraaz

March 12, 2015, 02:34		#7
monkey1 Senior Member Join Date: Jul 2011 Location: Berlin, Germany Posts: 173 Rep Power: 15	Didn't you name your parts when doing your mesh? When meshing you can name all surfaces by specific names (e.g. Door, Wall, Floor, WEindow 1, Window 2, etc.). Then it is easier to find them in pre. But you can also regroup several separate surfaces under one Part Name, e.g. if you have 10 windows on the left and 10 on the right, you can create one part "Windows Left" and selevt all 10 Windows on the left to be part of the group and the same for "Windows RIght". In Pre you would then only have to chose ONE part Name to acces 10 surfaces. BUT you should think about the Parts needed very carefully. Because if you suddenly need single suraces instead of the grouped ones, you are back to identifiying and selecting each surface one by one. I hope thats what you wanted to know

March 12, 2015, 03:52		#8
NewGuy New Member Join Date: Nov 2010 Posts: 7 Rep Power: 16	Hmm. Yes my geometry does consist of multibody parts named accordingly. It all shows up in mesh. However as you said I need 1 or 2 faces in a window or door in pre for example. In pre all the parts and their faces are numbered. So I have to pick one by one. I was just thinking whether there might be a better way to do this. Thanks.