CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > Siemens > STAR-CCM+

Model change: k-epsilon to k-omega SST results in divergence

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   November 23, 2011, 11:14
Default Model change: k-epsilon to k-omega SST results in divergence
  #1
New Member
 
Join Date: Nov 2011
Posts: 2
Rep Power: 0
kroetenwurz is on a distinguished road
Hey there,

At first, I am still a beginner in CFD with StarCCM+.
I have a simulation of a stirred tank reactor. Using the k-epsilon-model works fine and the solution converges. Now I want to run the same simulation with k-omega SST, but the solution doesn't converge. I didn't change any default values.

Do you have any general advices for me to achieve convergency?

Thank you and best wishes,
kw
kroetenwurz is offline   Reply With Quote

Old   November 23, 2011, 12:18
Default
  #2
Senior Member
 
Join Date: Mar 2009
Location: Austin, TX
Posts: 160
Rep Power: 18
kyle is on a distinguished road
Did it diverge or is it just oscillating? If your flow has unsteady features, they will show up more readily with K-omega than K-epsilon, even on a steady state simulation. K-epsilon is more diffusive, so it has a tendency to stamp out these oscillations.
kyle is offline   Reply With Quote

Old   November 24, 2011, 08:31
Default
  #3
New Member
 
Join Date: Nov 2011
Posts: 2
Rep Power: 0
kroetenwurz is on a distinguished road
At first it looked like that it wanted to diverge. I reduced the under-relaxation factors of Segrgated Flow, which helped. Now especially the Sdr-Plot is oscillating between 1e-4 and 1e-5 (no normilization).
kroetenwurz is offline   Reply With Quote

Reply

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
k-omega SST simulation of turbulent flow around a circular cylinder DanM OpenFOAM Running, Solving & CFD 17 October 13, 2016 14:29
expert parameters of SST model? David CFX 1 December 2, 2005 07:36
SST model with rough wall? David CFX 4 November 30, 2005 12:22
SST model Autometic wall function parameters? David CFX 0 November 24, 2005 05:47
about Y+ in SST model zuozicheng CFX 2 July 12, 2005 11:05


All times are GMT -4. The time now is 22:20.