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

Cavitation convergence problem

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

Reply
 
LinkBack Thread Tools Display Modes
Old   September 29, 2009, 10:41
Default Cavitation convergence problem
  #1
Member
 
Felipe Gutiérrez Donoso
Join Date: Mar 2009
Posts: 31
Rep Power: 8
Figd84 is on a distinguished road
i´m studying cavitation in a knife valve preceded by 3 plate-horifice devices. The geometry is 2D. I´ve done a steady, turbulent (k-epsilon) simulation to stablish a initial flow field without activating the cavitation model. After have a good convergence I´ve included the cavitation model, changing the pressure-velocity coupling to Simplec and linear pressure discretization.

I´ve been testing many under relaxation factors but I have divergence with every of them. I´ve tried unsteady solution with 0.0001s time step, but obtained the same result.

Any advice on this??

Thanks in advance
Figd84 is offline   Reply With Quote

Old   September 30, 2009, 01:21
Default
  #2
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 2,964
Rep Power: 30
-mAx- will become famous soon enough
Is your time step really adapted?
try to set dt as follow:
dt= 0.5 * (min cell size)/(max velocity expected)
For info, I set dt=1e-7..1e-6 for hydraulic devices
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   September 30, 2009, 14:46
Default
  #3
Member
 
Felipe Gutiérrez Donoso
Join Date: Mar 2009
Posts: 31
Rep Power: 8
Figd84 is on a distinguished road
I´ve reduced time step, it´s iterating now... I´ll let you know the results. Thanks
Figd84 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
Submerged fin, Convergence problem supermouniette FLUENT 10 July 6, 2009 10:47
convergence problem in comsol anderson Main CFD Forum 0 February 24, 2008 17:54
CONVERGENCE PROBLEM - oil boiler MM FLUENT 1 February 15, 2007 06:24
convergence problem with FLUENT cavitation model Belete Kiflie FLUENT 3 February 20, 2006 11:16
Non Convergence of 3D Heat transfer cfd problem Balraj Main CFD Forum 3 December 9, 2004 01:24


All times are GMT -4. The time now is 20:16.