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

SimpleFoam as laminar solver

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

Reply
 
LinkBack Thread Tools Display Modes
Old   March 24, 2006, 06:48
Default Hi, as simpleFoam is a stea
  #1
Member
 
Anja Stretz
Join Date: Mar 2009
Posts: 92
Rep Power: 8
anja is on a distinguished road
Hi,

as simpleFoam is a steady-state solver, the defined "timestep" is an iteration counter. Does that mean, that the "endTime" is the max number of iterations? And why is then within each timestep an iteration of p (in my case only in the beginning of the calculation, problem follows)

I want to calculate u and p but:
Time = 999
AMG: Solving for p, Initial residual = 1.02579e-06, Final residual = 2.76786e-07, No Iterations 1
time step continuity errors : sum local = 6.13966e-06, global = 5.96414e-08, cumulative = 0.000117451
ExecutionTime = 9411.37 s

Time = 1000
time step continuity errors : sum local = 1.01213e-05, global = -4.50328e-08, cumulative = 0.000117406
ExecutionTime = 9419.22 s


Thanks a lot for your help!
Anja
anja is offline   Reply With Quote

Old   March 24, 2006, 06:59
Default Yes, endTime is the max iterat
  #2
Senior Member
 
Hrvoje Jasak
Join Date: Mar 2009
Location: London, England
Posts: 1,763
Rep Power: 21
hjasak will become famous soon enough
Yes, endTime is the max iteration count. However, based on the snippet of the log file, you run has converged a long time ago. What you are seeing are the oscillations in the pressure due to round-off.

Have a look at the point where the momentum equation was solved last - this is where you should have stopped the solver. Note: the convergence checks in simpleFoam may be somewhat different to what you're used to: for example, if you want to converge the global residual to 1e-6, you should specify the linear solver convergence to be lower. Otherwise, as you approach the global convergence tolerance, the solver stops doing the work and nothing much happens. I personally always check the global convergence by hand (well, eyes) :-)

Enjoy,

Hrv
__________________
Hrvoje Jasak
Providing commercial FOAM/OpenFOAM and CFD Consulting: http://wikki.co.uk
hjasak is offline   Reply With Quote

Old   March 24, 2006, 08:20
Default Well, this is what I was using
  #3
Member
 
Anja Stretz
Join Date: Mar 2009
Posts: 92
Rep Power: 8
anja is on a distinguished road
Well, this is what I was using:
p AMG 1e-06 0 100;
U BICCG 1e-05 0.1;

What would you change?

How do you check the global convergence?

THANKS!
anja is offline   Reply With Quote

Old   April 5, 2007, 09:28
Default Hi world, I am in the same
  #4
lam
Member
 
Hoang-Lam
Join Date: Mar 2009
Location: Lausanne, Switzerland
Posts: 60
Rep Power: 8
lam is on a distinguished road
Hi world,

I am in the same situation like Anja:
I want my computation to stop when it reachs the criterium of convergence that I precise (the solver tolerance in system/fvSolution file, isn't it?), and not in function an arbitrary number of iterations (endtime, in system/controlDict in file).

Can somebody help me to do this, please?

Thanks in advance,

Lam
lam 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
SimpleFoam as Newtonian laminar flow solver titio OpenFOAM Running, Solving & CFD 2 March 8, 2013 05:44
OpenFoam profiling the solver simpleFoam andre OpenFOAM 8 April 7, 2011 21:39
Steady incompressible laminar flow using simpleFoam yongshenglian OpenFOAM Running, Solving & CFD 0 October 29, 2008 16:28
Dimension change in solver like simpleFoam booz OpenFOAM Running, Solving & CFD 2 August 21, 2008 11:35
SimpleFoam for laminar flow hsing OpenFOAM Running, Solving & CFD 3 April 14, 2005 14:39


All times are GMT -4. The time now is 05:35.