error when running icoFoam
Hi
I followed the instruction at http://openfoamwiki.net/index.php/Ho...ure_to_icoFoam to add temperature to icoFoam. I called the new solver "my_icoFoam." However, when I ran the solver, I got the following error message after t=0.195. I am wondering if anyone knows what they mean and how to solve this problem.Thanks! Code:
#0 Foam::error::printStack(Foam::Ostream&) in "/home/uiuc/OpenFOAM/uiuc-2.0.1/platforms/linuxGccDPOpt/lib/libOpenFOAM.so" |
What happened before the error message?
Code:
Floating point exception Dan |
Thanks, chegdan.
by accident I lost the original code, so I redid it. and it did not work. I decreased dt, and the courant number did decrease from Code:
Time = 0.005 Code:
Time = 5e-60 I was wondering if I should did some other change... |
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Dan |
Hello Daniel
Thanks for the quick reply my blockMeshDict is Code:
/*--------------------------------*- C++ -*----------------------------------*\ Code:
/*--------------------------------*- C++ -*----------------------------------*\ Code:
/*--------------------------------*- C++ -*----------------------------------*\ Code:
/*--------------------------------*- C++ -*----------------------------------*\ |
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hsingtzu,
I tried your case and there are several issues. 1. I rebuilt your mesh from the blockMeshDict you provided and it looks like the image below. is there something more that you do to create the mesh? you might want to try uploading your whole case to say dropbox (dropbox referral http://db.tt/hbaGBi5) and then post the link here when you put the case in the public folder on your dropbox 2. after running the checkMesh -allTopology -allGeometry command, I get some nasty messages. Code:
/*---------------------------------------------------------------------------*\ |
simpleFoam
Hi
I think it returns to your BC. you used zero gradient boundary for velocity on the cylinder which should be fixedValue of (0 0 0) to provide obstruction. But if you insist on using this BC for the cylinder you must change your solver to simpleFoam. Good luck |
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Also, for walls in your geometry...the patch type in the blockMeshDict should be wall and not patch. * By setting a zeroGradient for velocity at the cylinder patch with patch type "patch", it is creating an outflow condition (if that is what you wanted). * For a no-slip boundary, you will need a fixedValue (like you have), but with a patch type of wall. Hope this helps you. |
i'll flood the topic and ask u to work on the mesh quality. Can we have a look at your (desired) mesh?:D
tried ur dict and i got same pic as daniel :( |
2 Attachment(s)
Dear All
Thanks for all the comments. I should have double checked the geometry before copying it from OpenFOAM-2.0.1/run/tutorials/basic/potentialFoam/cylinder/constant/polyMesh. Actually I want to do my_icoFoam on model of "a cylinder inside a box" (please see the attached pic 1). I use the blockMeshDict from OpenFOAM-1.7.1 and it works. :) However, when I try a 3D box with 16 cylinders (4x4) inside (please see the attached pic 2),it gives me the following error message. (I have tried dt=0.0005 and dt= 0.000005. Both give me error messages. the following is the one with dt =0.000005. I have replaced "patch" with "wall" and set the BC of cylinder as "fixedValue; uniform (0 0 0);") Code:
Time = 0.005355 0/U can be found at http://dl.dropbox.com/u/20517550/4x4_3D/0/U 0/T can be found at http://dl.dropbox.com/u/20517550/4x4_3D/0/T constant/polyMesh/boundary can be found at http://dl.dropbox.com/u/20517550/4x4...yMesh/boundary please let me know if you would like to have access to some other files. Thanks Hsingtzu |
ok, starting to get somewhere.
1. you have some velocity inlets and those need to be type patch, outlets also need to be type patch instead of wall. 2. at pressure outlets, you need a fixedValue condition of type patch. 3. if you zip up everything in one directory and then provide the link to the zip file then we could try it. 4. I solve the same problem all the time with randomly packed cylinders http://www.personal.psu.edu/dab143/O...ombest2_ab.pdf |
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also(then) try setting the initial step to sth rly low, and check the first occurrence of co number and make sure it is below 1. And make sure ur getting fixed time steps by setting runTimeModifiable=no; Code:
startTime 0.0001; hope it helps u get ur solver working.. :rolleyes: |
Dear calim_cfd and chegdan
Thanks for your comments. I really appreciate your time and help. I am sorry for the late reply. I have been working on my final project which is due this Sun. This means that I will work on this problem next week. :) |
To Chegdan:
Thanks for your reply. I have changed the types of all boundary conditions to "patch". You may find the file at http://dl.dropbox.com/u/20517550/4x4.zip I appreciate your time and help. To calim-cfd: Thanks for your suggestions. :) Hsingtzu |
Hsingtzu,
Ok..I glanced at the case file and you have some problems. You have an inlet velocity and then many outflow (zeroGradient) boundary conditions for the velocity field. If you are modeling the flow around bluff bodies then you need some no-slip (ie fixedValue ) boundary conditions in there as was suggested by mohsen. I have something running on my workstation so I can't switch over and try your case immediately. Good Luck. Dan |
Thanks for your kind suggestion, Dan. :)
I should have paid attention to mohsen cheraghi's suggestion. Have a nice weekend. Hsingtzu |
Hi
I was trying to apply icoFoam to my model, but the courant # blew up at the first time step. Code:
Time = 5e-05 http://dl.dropbox.com/u/20517550/cell_3D.zip and I would appreciate any help. Thanks Hsingtzu |
first notes
a checkMesh reports: Code:
Checking geometry... i can see the mesh in paraview and it doesnt look that bad.. maybe you need to review the ordering of faces in blockMeshDict and if your mesh turns out still being bad then you'll need limited schemes and relaxation factors... get your mesh right first.. i dont have time to debugg yout blockmeshdict sry :( |
Hi calim_cfd
Thanks for mentioning "checkMesh". I did not think about it. Now I am working on the face pyramids. You mentioned that "the physics of your case is not properly set". Would you please give me some directions to work on? I used the cavity example of the official guide to make this model. Thanks Hsingtzu |
Then I solved the problem by giving up blockMesh thing and adopting gmsh.
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