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

long time for running porousSimpleFoam

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   July 14, 2017, 10:42
Default long time for running porousSimpleFoam
  #1
Senior Member
 
Ahmed Khattab's Avatar
 
ahmed
Join Date: Feb 2010
Posts: 182
Blog Entries: 1
Rep Power: 12
Ahmed Khattab is on a distinguished road
Dear Foamers,

i am running a case using simplePorousFoam, with total mesh of 900.000 cells, i think that OpenFOAM takes a long time to run the case. this is a sample for first iteration.
Code:
Time = 1

smoothSolver:  Solving for Ux, Initial residual = 1, Final residual = 6.71033e-10, No Iterations 34
smoothSolver:  Solving for Uy, Initial residual = 0.00118386, Final residual = 6.1944e-10, No Iterations 20
smoothSolver:  Solving for Uz, Initial residual = 1, Final residual = 4.55901e-10, No Iterations 32
GAMG:  Solving for p, Initial residual = 1, Final residual = 9.80576e-10, No Iterations 465
time step continuity errors : sum local = 1.5561e-06, global = 2.56885e-07, cumulative = 2.56885e-07
ExecutionTime = 114.83 s  ClockTime = 116 s
time of every step is decreasing in a slow rate, when it reached T= 5600 time became about 13 seconds. and there are residuals values.
Code:
Time = 5681

smoothSolver:  Solving for Ux, Initial residual = 2.17069e-07, Final residual = 4.33832e-10, No Iterations 10
smoothSolver:  Solving for Uy, Initial residual = 1.12953e-06, Final residual = 6.57395e-10, No Iterations 12
smoothSolver:  Solving for Uz, Initial residual = 5.88004e-07, Final residual = 3.57238e-10, No Iterations 12
GAMG:  Solving for p, Initial residual = 3.9218e-07, Final residual = 9.62315e-10, No Iterations 38
time step continuity errors : sum local = 1.74474e-07, global = 1.50349e-08, cumulative = 3.61903e-05
ExecutionTime = 35684.6 s  ClockTime = 43420 s
solver used are GAMG for pressure with tolerance 1e-09 and relative tolerance 0.0.
smooth solver used for velocity with same criteria.
Ahmed Khattab is offline   Reply With Quote

Old   July 17, 2017, 04:39
Default
  #2
Senior Member
 
Tom Fahner
Join Date: Mar 2009
Location: Breda, Netherlands
Posts: 565
Rep Power: 22
tomf will become famous soon enough
Send a message via MSN to tomf Send a message via Skype™ to tomf
Hi,

I think you should use a relative tolerance of 0.01 for pressure and 0.1 for velocity. There is no need to solve for the absolute tolerance in the beginning with the steady state solver.

You will see that you will have much less iterations for the linear solvers and the total run will take much less time.

Regards,
Tom
tomf is offline   Reply With Quote

Reply

Tags
poroussimplefoam, residual, time

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
AMI speed performance danny123 OpenFOAM 21 October 24, 2020 05:13
bash script for pseudo-parallel usage of reconstructPar kwardle OpenFOAM Post-Processing 39 July 1, 2020 10:13
How to export time series of variables for one point? mary mor OpenFOAM Post-Processing 8 July 19, 2017 11:54
same geometry,structured and unstructured mesh,different behaviour. sharonyue OpenFOAM Running, Solving & CFD 13 January 2, 2013 23:40
Missing math.h header Travis FLUENT 4 January 15, 2009 12:48


All times are GMT -4. The time now is 09:16.