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

numeric schemes

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

Like Tree6Likes
  • 2 Post By akidess
  • 4 Post By AndreasG

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 30, 2013, 16:44
Default numeric schemes
  #1
Super Moderator
 
Tobi's Avatar
 
Tobias Holzmann
Join Date: Oct 2010
Location: Tussenhausen
Posts: 2,708
Blog Entries: 6
Rep Power: 51
Tobi has a spectacular aura aboutTobi has a spectacular aura aboutTobi has a spectacular aura about
Send a message via ICQ to Tobi Send a message via Skype™ to Tobi
Dear all,

what whould you use for U/k/epsilon etc. . . .

Code:
BICCG
GAMG
PBiCG
smoothSolver
Thanks in advance,
Tobi
Tobi is offline   Reply With Quote

Old   October 1, 2013, 03:49
Default
  #2
Senior Member
 
akidess's Avatar
 
Anton Kidess
Join Date: May 2009
Location: Germany
Posts: 1,377
Rep Power: 29
akidess will become famous soon enough
The first three solvers should always outperform smoothSolver. GAMG should outperform CG methods when not limited by communication (this is especially true for the pressure equation). If you're in doubt, just run a couple fixed timesteps with each of the solvers and you will very quickly find out where you can save time.

Quote:
Originally Posted by Tobi View Post
Dear all,

what whould you use for U/k/epsilon etc. . . .

Code:
BICCG
GAMG
PBiCG
smoothSolver
Thanks in advance,
Tobi
cfdonline2mohsen and Tobi like this.
__________________
*On twitter @akidTwit
*Spend as much time formulating your questions as you expect people to spend on their answer.
akidess is offline   Reply With Quote

Old   October 1, 2013, 04:19
Default
  #3
New Member
 
Andreas Groß
Join Date: Sep 2013
Posts: 8
Rep Power: 12
AndreasG is on a distinguished road
As akidess already said, for p a good choice should be GAMG, for other fields I usually use PBiCG.

BICCG shouldn't be used any more:
Quote:
Diagonal incomplete LU preconditioned BiCG solver derived from the general preconditioned BiCG solver PBiCG but with the choice of preconditioner pre-selected. Deprecated:This solver is present for backward-compatibility and the PBiCG solver should be used instead. (deprecated Apr 2008)
source: http://foam.sourceforge.net/docs/cpp/a00098.html
AndreasG is offline   Reply With Quote

Old   October 7, 2013, 08:47
Default
  #4
Senior Member
 
cfdonline2mohsen's Avatar
 
Mohsen KiaMansouri
Join Date: Jan 2010
Location: CFD Lab
Posts: 118
Rep Power: 16
cfdonline2mohsen is on a distinguished road
Dear Foamers
Have a look at the following references for more details:

P. K. Khosla, and S. G. Rubin, “A diagonally dominant second-order accurate implicit scheme”, Computers and Fluids, 2:207-209, 1974.

M. R. Hestens, and E. L. Steifel, “Method of conjugate gradients for solving
linear systems”, Journal of Research, 29:409-436, 1952.

D. A. H. Jacobs, “Preconditioned Conjugate Gradient methods for solving
systems of algebraic equations”, Central Electricity Research Laboratories
Report, RD/L/N193/80, 1980.

H. A. Van Der Vorst, “Bi-CGSTAB: A fast and smoothly converging variant of Bi-CG for the solution of nonsymmetric linear systems”, SIAM J. Scientific Computing, 13(2):631-644, 1992.
__________________
“If you have an apple and I have an apple and we exchange these apples then you and I will still each have one apple. But if you have an idea and I have an idea and we exchange these ideas, then each of us will have two ideas.”
cfdonline2mohsen is offline   Reply With Quote

Old   October 8, 2013, 23:52
Default
  #5
Member
 
skyinventorbt's Avatar
 
Dr. B T KANNAN
Join Date: Jul 2011
Location: CHENNAI (MADRAS), INDIA
Posts: 55
Rep Power: 14
skyinventorbt is on a distinguished road
PBiCG is good.
--
KANNAN
skyinventorbt 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
numeric schemes Tobi OpenFOAM Running, Solving & CFD 0 August 13, 2012 08:00
Better organization of Convective Term approximation schemes Michail CFD-Wiki 0 March 15, 2012 12:56
time stepping schemes for compressible DNS/LES shyamdsundar Main CFD Forum 0 January 14, 2010 23:15
ENERGY CONSERVATION SCHEMES! Science Seeker Main CFD Forum 1 May 24, 2001 12:13
Higher-order bounded convection schemes for pure advection with discontinuity Anthony Main CFD Forum 3 June 13, 1999 02:36


All times are GMT -4. The time now is 06:36.