CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > FLOW-3D

f-packing

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

Like Tree1Likes
  • 1 Post By dmilano

Reply
 
LinkBack Thread Tools Display Modes
Old   March 21, 2013, 21:12
Default f-packing
  #1
Member
 
bird
Join Date: Sep 2012
Posts: 42
Rep Power: 4
pyxbird is on a distinguished road
Dear all,
Hi, sometimes flow3d just recommends me to ruduce the f-packing coefficient(cfpk) by factor of 10, and its default value is 1, that means I should change it into 0.1.
I want to ask, does the value of this coefficient make sense significantly?
What's the difference between 1 and 0.1, will it influence the outcome of the simulation greatly? I am still confused after reading the mannal given by the software.
pyxbird is offline   Reply With Quote

Old   March 25, 2013, 10:13
Default
  #2
Member
 
Join Date: Mar 2012
Posts: 71
Rep Power: 5
dmilano is on a distinguished road
The f-packing algorithm is intended to prevent voids from opening inside of continuous fluid regions due to roundoff errors. It is a numerical adjustment, so the coefficient has little physical meaning. Adjusting the coefficient controls the strength of the adjustment and usually does not have a significant impact on the results. There is a caveat here: values that are too small will prevent the algorithm from operating as intended, while values that are too large may influence the solution. The latter scenario is a very rare case and is easily avoidable if you do not increase the f-packing coefficient above the default value of one.
mf_emp likes this.
dmilano is offline   Reply With Quote

Old   March 25, 2013, 20:11
Default
  #3
Member
 
bird
Join Date: Sep 2012
Posts: 42
Rep Power: 4
pyxbird is on a distinguished road
Quote:
Originally Posted by dmilano View Post
The f-packing algorithm is intended to prevent voids from opening inside of continuous fluid regions due to roundoff errors. It is a numerical adjustment, so the coefficient has little physical meaning. Adjusting the coefficient controls the strength of the adjustment and usually does not have a significant impact on the results. There is a caveat here: values that are too small will prevent the algorithm from operating as intended, while values that are too large may influence the solution. The latter scenario is a very rare case and is easily avoidable if you do not increase the f-packing coefficient above the default value of one.
Thank you!
pyxbird 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
Fluent convergence for particles packing natantyt FLUENT 0 March 7, 2012 13:02
Fluent Convergence for particles packing natantyt FLUENT 0 March 7, 2012 13:01
1st prob: code 123 error | 2nd prob: max. packing Ferzola CFX 0 November 21, 2008 13:43
packing materials shankar FLUENT 2 October 4, 2006 23:54
Packing limit management in the Eulerian model ap FLUENT 2 September 16, 2005 17:46


All times are GMT -4. The time now is 15:54.