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

FVDOM instability in wedge-type mesh

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

Like Tree1Likes
  • 1 Post By Yuri Almeida

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 12, 2014, 10:14
Default FVDOM instability in wedge-type mesh
  #1
New Member
 
Yuri Almeida
Join Date: Jan 2012
Location: Rio de Janeiro, Brazil
Posts: 21
Rep Power: 13
Yuri Almeida is on a distinguished road
Dear FOAMers,

I've been simulating a burner using a wedge-type mesh, like the one in Fluent tutorial, and I'm having difficulties when I turn on the FVDOM radiation model.

Apparently, the rays in the FVDOM model which point to the axis (center line of the wedge) do not converge. The initial residual for these rays keeps rising after each radiation iteration until the solver blows up.

I've started to think that an incompatibility between the FVDOM and the wedge boundary condition exists.

I'm using OF 2.2.x and the fireFoam solver.

Has anyone here successfully applied the FVDOM in a wedge-type simulation?

Best,
fcrl-zxr likes this.
Yuri Almeida is offline   Reply With Quote

Old   September 21, 2014, 13:28
Default
  #2
New Member
 
Justin Hwang
Join Date: Jul 2014
Location: California
Posts: 2
Rep Power: 0
shininiu is on a distinguished road
Hi Yuri,

Did you have any luck getting fvDOM model to work in a wedge geometry?
I ran into a similar problem- reactingFoam+radiation solver, wedge geometry, and fvDOM model. The problems I noticed are;

1. even though it's a 2-D solution, when nTheta=0 gives a floating point exception error. nTheta=1 will give no error.

2. solution won't converge, always hitting the 1000 iteration limit.

I'm very new to CFD in general, so please let me know if I missed something obvious.
Thank you,
shininiu is offline   Reply With Quote

Old   September 21, 2014, 13:56
Default
  #3
New Member
 
Yuri Almeida
Join Date: Jan 2012
Location: Rio de Janeiro, Brazil
Posts: 21
Rep Power: 13
Yuri Almeida is on a distinguished road
Hi shininiu,

Unfortunately, I couldn't overcome this issue with FVDOM in a wedge geometry. I tried to use P1 instead of FVDOM but the results were poor compared with no radiation.

I should highlight that using a wedge geometry is different than simulate a 2D case. Actually, a wedge geometry is a 3D case, as you can see from the 3 velocity components calculated during the simulation. So, it's expected that FVDOM gives an error if you try to put nTheta=0, since it's a 3D case.

However, FVDOM seems to have a problem with wedge BC. The axis should work as a reflective surface, returning back to the domain all radiation carried by the rays (as supposed to occur with a symmetric case), but I noted that the radiation starts to accumulate in the axis, always leading to blow up the solver. And I have no idea how to fix it...

A simple solution could be to set a fixed source term in the energy equation, for example -0.1*Q_c, considering that the system is losing 10% of the generated heat by the radiation. But it is only a suggestion.

Good luck!
Yuri Almeida is offline   Reply With Quote

Old   September 21, 2014, 14:11
Default
  #4
New Member
 
Justin Hwang
Join Date: Jul 2014
Location: California
Posts: 2
Rep Power: 0
shininiu is on a distinguished road
Ah... wedge being 3D makes a lot of sense... I was just wondering about non-zero z-components!

I think I'll move on without validating fvDOM model. (The wedge case was my validation case.) At least fortunately, my research case is not a wedge...

Thank you for the suggestion and the insight.
shininiu is offline   Reply With Quote

Old   November 9, 2017, 23:41
Default Please take a look at this thread for possible solution
  #5
Member
 
Jaydeep
Join Date: Jun 2015
Posts: 34
Rep Power: 9
jaydeep is on a distinguished road
Hi Guys,

please take a look at this thread: fvDOM OpenFOAM wedge type patch
jaydeep is offline   Reply With Quote

Reply

Tags
combustion, convergence, firefoam, fvdom, radiation

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
second order schemes marine OpenFOAM 67 April 11, 2022 19:19
Inlet patch problems martyn88 OpenFOAM Running, Solving & CFD 6 April 21, 2017 19:34
turbulent jet simulation antonio_ing OpenFOAM Running, Solving & CFD 5 September 16, 2010 03:31
pipe flow with heat transfer Fabian OpenFOAM 2 December 12, 2009 05:53
fluent add additional zones for the mesh file SSL FLUENT 2 January 26, 2008 12:55


All times are GMT -4. The time now is 06:55.