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

Residuals - Multiphase

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

Reply
 
LinkBack Thread Tools Display Modes
Old   February 12, 2014, 19:35
Default Residuals - Multiphase
  #1
New Member
 
cfd^2
Join Date: Mar 2013
Posts: 28
Rep Power: 5
cfd^2 is on a distinguished road
Hi,

I am simulating two phase gas-liquid flow with vof implicit (timestep=0.01s) using compressive scheme for volume fraction. The geometry is tree-shaped, the gas enter in one inlet and the liquid in another inlet. I am getting the strange convergence pattern of the image attached. Is it decent or something is really wrong?
Attached Images
File Type: jpg residuals.jpg (68.4 KB, 20 views)
cfd^2 is offline   Reply With Quote

Old   February 13, 2014, 08:00
Default
  #2
New Member
 
cfd^2
Join Date: Mar 2013
Posts: 28
Rep Power: 5
cfd^2 is on a distinguished road
NOTE: later it diverges in y-momenum.
cfd^2 is offline   Reply With Quote

Old   February 13, 2014, 10:01
Default
  #3
Senior Member
 
ghost82's Avatar
 
Daniele
Join Date: Oct 2010
Location: Italy
Posts: 987
Rep Power: 16
ghost82 will become famous soon enough
Hi!
something is wrong
you have not a converged solution; I would check the mesh/time step.

Daniele
ghost82 is offline   Reply With Quote

Old   February 13, 2014, 15:54
Default
  #4
New Member
 
cfd^2
Join Date: Mar 2013
Posts: 28
Rep Power: 5
cfd^2 is on a distinguished road
It seems that I need a mesh very refined and a very small timestep to avoid divergence using implicit vof. I was running explicit vof with coarser mesh (but even lower timestep) using geo-reconstruct. So, the explicit vof seems to be better for this case, despite the high cost.
cfd^2 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
motorBike Residuals for SST k-omega... and mine JR22 OpenFOAM Running, Solving & CFD 6 August 1, 2013 09:08
what to monitor besides residuals? franzdrs FLUENT 5 March 21, 2013 04:59
judging convergence through residuals MachZero Main CFD Forum 7 December 25, 2012 13:18
Strange residuals of the Density Based Solver Pat84 FLUENT 0 October 22, 2012 15:59
Convergence - scaled vs unscaled residuals HS FLUENT 1 November 7, 2005 06:45


All times are GMT -4. The time now is 17:20.