CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM

chtMultiRegionFoam: fluid-fluid interface

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree1Likes
  • 1 Post By Linse

Reply
 
LinkBack Thread Tools Display Modes
Old   May 3, 2012, 08:38
Default chtMultiRegionFoam: fluid-fluid interface
  #1
Senior Member
 
Samuele Z
Join Date: Oct 2009
Location: Mozzate - Co - Italy
Posts: 490
Rep Power: 9
samiam1000 is on a distinguished road
Dear All,

I am trying to use the different tutorial that deals with the chtMultiRegionFoam solver, but I can not find what I am looking for.

I see hot to treat the fluid-solid interface between region, but I can not understand how to treat the solid-solid and the fluid-fluid interface.

Which are the right BC on epsilon, k, U, p, p_rgh, T and so on on these interfaces?

Thanks for help,

Samuele
samiam1000 is offline   Reply With Quote

Old   May 3, 2012, 10:01
Default
  #2
Senior Member
 
Join Date: Mar 2011
Posts: 174
Rep Power: 6
anon_a is on a distinguished road
I will attempt to answer your question, not because I am sure about the answer but rather to see if I have it right in my mind.

In the chtMultiRegionFoam/multiRegionHeater we can see that all interfaces of the heater with the rest of the parts have the same BC for the temperature:
Code:
            "heater_to_.*"
            {
                type            compressible::turbulentTemperatureCoupledBaffleMixed;
                neighbourFieldName T;
                K               solidThermo;
                KName           none;
                value           uniform 300;
            }
Since the heater is a neighbour of both the gas and the solid, I believe this answers your question about solid-solid: you use pretty much the same BC as in solid-gas. If I remember well, this just imposes the same temperature and heat flux on both sides. The rest of the quantities you wrote about (epsilon, k, U, p, p_rgh) do not exist in the solid anyway.

As for the fluid-fluid: why do you have an interface in the first place? Can't you join these two parts? if you can't, you might need significant modifications in the solver.
anon_a is offline   Reply With Quote

Old   May 3, 2012, 10:13
Default
  #3
Senior Member
 
Samuele Z
Join Date: Oct 2009
Location: Mozzate - Co - Italy
Posts: 490
Rep Power: 9
samiam1000 is on a distinguished road
Dear anon_a,

thanks for answering.

Actually, as far as the solid-solid interface is concerned, you're right. It's enough to use the same BC that are used in the tutorial.

Also, I have 2 different fluid region because I would like to be able (but I need to modify the solver and I've not been able, yet) to impose the temperature in a certain FLUID volume, which is connected with another fluid volume. Altough I can't run my new solver, yet, I have a mesh with 2 detached fluid regions, with an interface. I thought that a zeroGradient condition was ok, but that's not true.

The simulation, in fact, seems to explode and it's like a source appear on the interface.

Anyother idea?

Do you think I should `unify the 2 regions'? Can't I deal a domain with to fluid regions detached by an interface?
samiam1000 is offline   Reply With Quote

Old   May 3, 2012, 10:32
Default
  #4
Senior Member
 
Bernhard Linseisen
Join Date: May 2010
Location: Magdeburg/Geneva
Posts: 178
Blog Entries: 1
Rep Power: 7
Linse is on a distinguished road
Hi Samuele,

If it really is just about imposing a different temperature on one of two fluid zones, I suggest using the "setFields" utility. That is much easier than writing a new solver, getting two zones to cooperate easily.

Nevertheless, if you made progress on the fluid-fluid-thingy, I would be happy if you could share your knowledge with me. Because at the moment I am trying to do something very similar. ;-)
samiam1000 likes this.
Linse is offline   Reply With Quote

Old   May 3, 2012, 10:39
Default
  #5
Senior Member
 
Samuele Z
Join Date: Oct 2009
Location: Mozzate - Co - Italy
Posts: 490
Rep Power: 9
samiam1000 is on a distinguished road
Dear Bernhard,

of course I will share what I will discover.

And what about the setField? I need to impose temertature, but I need that it remains constant during the whole simulation. I was thinking about explicitSetValue (but it's not implemented in the multi regions solver). That's why I was editing the source.

Can I solve this with the setFields option?

Also, what about writing via email (samuele.zampini@gmail.com)? That would be much easier and we could post something useful if we reach our goal.

Samuele.
samiam1000 is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
move wall and refine mesh at fluid interface Jimbomet OpenFOAM Running, Solving & CFD 6 December 4, 2014 14:17
fluid to solid heattransfer with chtMultiRegionFoam schteff OpenFOAM 5 August 20, 2010 07:45
Increasing chtMultiRegionFoam Fluid Temperature m.nichols19 OpenFOAM 0 June 28, 2010 15:11
Boundary conditions at Fluid Solid interface (CHT) michelle CFX 1 April 21, 2008 04:06
how to use fluid fluid interface Beno CFX 0 July 13, 2005 14:08


All times are GMT -4. The time now is 23:21.