CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Running, Solving & CFD

porosity and buoyancy

Register Blogs Community New Posts Updated Threads Search

Like Tree2Likes
  • 1 Post By vainilreb
  • 1 Post By vainilreb

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   November 2, 2013, 16:08
Default porosity and buoyancy
  #1
Member
 
Robert
Join Date: Aug 2012
Location: Berlin
Posts: 74
Rep Power: 14
vainilreb is on a distinguished road
Hi there,

has anyone of you ever successfully set up a case with a porosity zone, using chtMultiRegionFoam or at least any solver that solves for p_rgh instead of p?

You might have notices from the large amount of threads I have posted on this topic, that I have already had a hard time trying to do so and I finally got to the point of saying: it simply won't work with openfoam.

I hope there's someone out there who disagrees with my opinion - and maybe is able and willing to help.

Best,

Robert
vainilreb is offline   Reply With Quote

Old   November 4, 2013, 06:00
Default
  #2
Member
 
Robert
Join Date: Aug 2012
Location: Berlin
Posts: 74
Rep Power: 14
vainilreb is on a distinguished road
I think I may have found the reason for chtMultiRegionFoam not working with an explicitPorositySource in the fvOptions file.

In the UEqn.h fvOptions(rho, U) usually is added to the rhs (e.g. in chtMultiRegionSimpleFoam and rhoPimpleFoam). In the UEqn.h of chtMultiRegionFoam, fvOptions(rho, U) is added to the left hand side, which should mean it has the opposite effect. Now the strange pressure behaviour along the probe seems quite reasonable to me.

I think this is a bug, what do you think?
dancoz87 likes this.
vainilreb is offline   Reply With Quote

Old   November 4, 2013, 07:35
Default
  #3
Member
 
Robert
Join Date: Aug 2012
Location: Berlin
Posts: 74
Rep Power: 14
vainilreb is on a distinguished road
It works! For those who want to use explicitPorositySource with chtMultiRegionFoam, you have to change

tmp<fvVectorMatrix> UEqn
(
fvm::ddt(rho,U)
+ fvm::ddt(phi,U)
+ turb.devDevRhoReff(U)
+ fvOptions(rho,U)
);

to

tmp<fvVectorMatrix> UEqn
(
fvm::ddt(rho,U)
+ fvm::ddt(phi,U)
+ turb.devDevRhoReff(U)
==
fvOptions(rho,U)
);

and the porositySource works properly.
dancoz87 likes this.
vainilreb is offline   Reply With Quote

Reply


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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
How tensor parameters to be entered in CFX-pre? hadi.iraji CFX 1 May 7, 2013 05:03
Simulation of a Silo Attesz CFX 20 October 15, 2010 09:11
air bubble is disappear increasing time using vof xujjun CFX 9 June 9, 2009 08:59
Porosity and buoyancy Guillaume CFX 3 June 5, 2006 12:51


All times are GMT -4. The time now is 02:38.