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

About icoFoam case

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

Reply
 
LinkBack Thread Tools Display Modes
Old   December 14, 2005, 12:09
Default Dear all, I am trying to ru
  #1
Senior Member
 
Guoxiang
Join Date: Mar 2009
Posts: 109
Rep Power: 8
liugx212 is on a distinguished road
Dear all,

I am trying to run the icoFoam cavity case with the block size of 92*92*32 and defult sets. But I was told the error of time as follows. Could you please help me see and give advice?

Thanks a lot.

Errors:

Time = 0.02

Mean and max Courant Numbers = 0.109749 132.97
BICCG: Solving for Ux, Initial residual = 0.769511, Final residual = 9.41873e-06, No Iterations 38
BICCG: Solving for Uy, Initial residual = 0.725626, Final residual = 3.13877e-06, No Iterations 36
BICCG: Solving for Uz, Initial residual = 0.8086, Final residual = 9.13794e-06, No Iterations 35ICCG: Solving for p, Initial residual = 0.953251, Final residual = 9.12515e-07, No Iterations 265
time step continuity errors : sum local = 3.04285e-07, global = 1.32364e-18, cumulative = 1.65714e-18
ICCG: Solving for p, Initial residual = 0.841697, Final residual = 9.02924e-07, No Iterations 242
time step continuity errors : sum local = 1.65841e-06, global = 5.28474e-18, cumulative = 6.94188e-18
ExecutionTime = 192.11 s


Time = 0.025

Mean and max Courant Numbers = 1.37811 15395.5
BICCG: Solving for Ux, Initial residual = 0.997305, Final residual = 0.0301471, No Iterations 1001
BICCG: Solving for Uy, Initial residual = 0.997675, Final residual = 15.8377, No Iterations 1001BICCG: Solving for Uz, Initial residual = 0.999334, Final residual = 0.00554499, No Iterations 1001
ICCG: Solving for p, Initial residual = 0.999822, Final residual = 9.36367e-07, No Iterations 124
time step continuity errors : sum local = 0.00903109, global = -3.98103e-15, cumulative = -3.97409e-15
ICCG: Solving for p, Initial residual = 0.998574, Final residual = 9.58777e-07, No Iterations 132
time step continuity errors : sum local = 5.25563, global = 4.08839e-11, cumulative = 4.08799e-11ExecutionTime = 748.68 s


Time = 0.03

Mean and max Courant Numbers = 1.61369e+06 5.99557e+10
BICCG: Solving for Ux, Initial residual = 1, Final residual = 1, No Iterations 1001
BICCG: Solving for Uy, Initial residual = 1, Final residual = 1, No Iterations 1001
BICCG: Solving for Uz, Initial residual = 1, Final residual = 1, No Iterations 1001
ICCG: Solving for p, Initial residual = 1, Final residual = 51.6963, No Iterations 5001
time step continuity errors : sum local = 2.80935e+17, global = 2.2091, cumulative = 2.2091
ICCG: Solving for p, Initial residual = 1, Final residual = 56.148, No Iterations 5001
time step continuity errors : sum local = 7.65932e+26, global = -1.49149e+09, cumulative = -1.49149e+09
ExecutionTime = 1827.63 s


End
liugx212 is offline   Reply With Quote

Old   December 14, 2005, 12:52
Default I may be wrong, but looks like
  #2
New Member
 
Charles Ju
Join Date: Mar 2009
Posts: 15
Rep Power: 8
ploceus is on a distinguished road
I may be wrong, but looks like your mesh is too fine. Maybe you can try to reduce time step.
Regards.
ploceus is offline   Reply With Quote

Old   December 14, 2005, 13:01
Default Dear Charles Ju: Thanks for
  #3
Senior Member
 
Guoxiang
Join Date: Mar 2009
Posts: 109
Rep Power: 8
liugx212 is on a distinguished road
Dear Charles Ju:

Thanks for your advice. my using time step is 0.005 and stop on 0.03. writeInterval is 1. Please give more details.

Thanks deeply.
Guoxiang
liugx212 is offline   Reply With Quote

Old   December 14, 2005, 13:34
Default Hi. Maybe time step = 0.001 o
  #4
New Member
 
Charles Ju
Join Date: Mar 2009
Posts: 15
Rep Power: 8
ploceus is on a distinguished road
Hi.
Maybe time step = 0.001 or 0.0001?
Or you could increase cell sizes.
Also wrong boundary conditions will cause diverging solutions. Check them too.
Regards.
ploceus is offline   Reply With Quote

Old   December 14, 2005, 13:47
Default Dear Charles Ju: Thanks ag
  #5
Senior Member
 
Guoxiang
Join Date: Mar 2009
Posts: 109
Rep Power: 8
liugx212 is on a distinguished road
Dear Charles Ju:

Thanks again. I will check as you said. By the way, the boundary conditions were checked which was ok by run checkMesh. I am not sure whether it is ok or not.

I will tell you after test.


Thanks deeply.
Guoxiang
liugx212 is offline   Reply With Quote

Old   December 14, 2005, 14:14
Default Boundary condition are checked
  #6
liu
Senior Member
 
Xiaofeng Liu
Join Date: Mar 2009
Location: State College, PA, USA
Posts: 118
Rep Power: 8
liu is on a distinguished road
Boundary condition are checked by yourself, not checkMesh.

Do some coarse mesh calculation to see what will happen.
__________________
Xiaofeng Liu, Ph.D., P.E.,
Assistant Professor
Department of Civil and Environmental Engineering
Penn State University
223B Sackett Building
University Park, PA 16802


Web: http://water.engr.psu.edu/liu/
liu is offline   Reply With Quote

Old   December 14, 2005, 14:15
Default Dear Charles Ju: I have ch
  #7
Senior Member
 
Guoxiang
Join Date: Mar 2009
Posts: 109
Rep Power: 8
liugx212 is on a distinguished road
Dear Charles Ju:

I have change as you said, but the problem is same. Do you have another advice?

Thanks deeply.
Guoxiang
liugx212 is offline   Reply With Quote

Old   December 14, 2005, 16:40
Default Dear Xiaofeng: Thanks a lot
  #8
Senior Member
 
Guoxiang
Join Date: Mar 2009
Posts: 109
Rep Power: 8
liugx212 is on a distinguished road
Dear Xiaofeng:

Thanks a lot. Just now, I checked the boundary file. My nFaces is: 28704, but the startFace is: 798192 So I think something is wrong here since startFace is further more the nFace. Could you please give some advice?

Thanks deeply,
Guoxiang
liugx212 is offline   Reply With Quote

Old   December 15, 2005, 16:59
Default Dear All, I still do not so
  #9
Senior Member
 
Guoxiang
Join Date: Mar 2009
Posts: 109
Rep Power: 8
liugx212 is on a distinguished road
Dear All,

I still do not solve this questions yet. I have changed to small time step and checked the boundary. It likes ok. But the "time step continuity errors :" problem is still here. Could you please help me?
liugx212 is offline   Reply With Quote

Old   December 17, 2005, 14:44
Default Obviously something is wrong w
  #10
unoder
Guest
 
Posts: n/a
Obviously something is wrong with one of your files, so why don't you just copy a whole new/fresh icoFoam cavity case from inside /tutorials directory and then run blockMesh and icoFoam.

AFAIR there's also an .allrun file which works straight "out-of-the-box".
  Reply With Quote

Old   December 17, 2005, 14:49
Default Dear Martin Jørgensen: Than
  #11
Senior Member
 
Guoxiang
Join Date: Mar 2009
Posts: 109
Rep Power: 8
liugx212 is on a distinguished road
Dear Martin Jørgensen:

Thanks for your help.
You mean I should use Allrun to instead of the blockMesh and icoFoam. Right?

Thanks again.
Guoxiang
liugx212 is offline   Reply With Quote

Old   December 17, 2005, 15:29
Default Hi Guoxiang, I mean: (under
  #12
unoder
Guest
 
Posts: n/a
Hi Guoxiang,

I mean: (under linux), standing inside your working directory - that would probably be something like (can't exactly remember if this path is correct, however here we go):

cd /home/guoxiang/OpenFOAM/OpenFOAM-1.2/guoxiang-1.2/run/tutorials

I would then do a recursive remove on this directory that doesn't work "rm -rf icoFoam/cavity" - notice that you should make sure you have a backup somewhere of the original directory which in my place would be in something like /OpenFOAM/OpenFOAM-1.2/run/tutorials. If you did like in the readme file that ships with openfoam, you would also have a backup.

So, standing in your working directory:

"cp -r /OpenFOAM/OpenFOAM-1.2/run/tutorials/icoFoam/cavity (place you want your working copy like for instance .)"

Then ./allrun worked for me (blockMesh and icoFoam should also work) as far as I remember and once you made sure everything is okay, you can experiment by changing mesh grading etc (in blockMeshDict-file).

I assume you once already have solved this case, right?
  Reply With Quote

Old   December 17, 2005, 18:43
Default Dear Martin Jørgensen: Tha
  #13
Senior Member
 
Guoxiang
Join Date: Mar 2009
Posts: 109
Rep Power: 8
liugx212 is on a distinguished road
Dear Martin Jørgensen:

Thanks a lot.
Just now, I have tries as you said, But the problem is still same. Could you have another advice?

Thank you very much.
xiang
liugx212 is offline   Reply With Quote

Old   December 18, 2005, 10:42
Default Yep, attach your case here in
  #14
unoder
Guest
 
Posts: n/a
Yep, attach your case here in a compressed file so others can download it and try for themselves.
  Reply With Quote

Old   December 18, 2005, 14:28
Default Dear Martin Jørgensen: I ha
  #15
Senior Member
 
Guoxiang
Join Date: Mar 2009
Posts: 109
Rep Power: 8
liugx212 is on a distinguished road
Dear Martin Jørgensen:

I have a test when I reinstalled. But the question is still here. It is very strange. I use the cavity in icoFoam case. I have really no idea. I do not how to do?

Thanks a lot.
xiang
liugx212 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
IcoFoam aap OpenFOAM Running, Solving & CFD 15 May 28, 2012 08:30
Density in icoFoam Densidad en icoFoam manuel OpenFOAM Running, Solving & CFD 8 September 22, 2010 04:10
About phi in icoFoam kar OpenFOAM Running, Solving & CFD 3 February 20, 2008 06:20
Cloning a case or creating a new case for 16 processes mellanoxuser OpenFOAM Running, Solving & CFD 0 February 8, 2008 17:52
IcoFoam on AIX 53 ds2taieb OpenFOAM Installation 1 March 24, 2006 04:22


All times are GMT -4. The time now is 19:50.