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

Tutorial bigWave

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

Reply
 
LinkBack Thread Tools Display Modes
Old   May 13, 2010, 08:18
Default Tutorial bigWave
  #1
New Member
 
Jochem
Join Date: May 2010
Posts: 28
Rep Power: 7
Jochem is on a distinguished road
Hi,

I am new in OpenFoam. I am trying to do the tutorial bigWave. I am having some trouble with the snappyHexMesh. I've runned the blockMesh first as described in the tutorial. After this i had to make an empty directory 'triSurface'. This is no problem.

The next thing i have to do is to run snappyHexMesh with the -overwrite option using 'snappyHexMesh -overwrite'. This command should write the mesh into the constant/polyMesh directory. But OpenFoam gives me an error. This is the error i get :

Create time

Create mesh for time = 0

Read mesh in = 0.09 s

Overall mesh bounding box : (0 0 0) (200 200 90)
Relative tolerance : 1e-06
Absolute matching distance : 0.000296816

Reading refinement surfaces.
Read refinement surfaces in = 0 s

Reading refinement shells.
Refinement level 1 for all cells inside refinementBox
Read refinement shells in = 0 s

Setting refinement level of surface to be consistent with shells.
Checked shell refinement in = 0 s


Determining initial surface intersections
-----------------------------------------



--> FOAM FATAL ERROR:
Number of cells in mesh:13500 does not equal size of cellLevel:55412
This might be because of a restart with inconsistent cellLevel.

From function hexRef8::getLevel0EdgeLength() const
in file polyTopoChange/polyTopoChange/hexRef8.C at line 358.

FOAM aborting

#0 Foam::error:rintStack(Foam::Ostream&) in "/home/jochem.vermeir/OpenFOAM/OpenFOAM-1.6.x/lib/linux64GccDPOpt/libOpenFOAM.so"
#1 Foam::error::abort() in "/home/jochem.vermeir/OpenFOAM/OpenFOAM-1.6.x/lib/linux64GccDPOpt/libOpenFOAM.so"
#2 Foam::hexRef8::getLevel0EdgeLength() const in "/home/jochem.vermeir/OpenFOAM/OpenFOAM-1.6.x/lib/linux64GccDPOpt/libdynamicMesh.so"
#3 Foam::hexRef8::hexRef8(Foam:olyMesh const&, Foam::List<int> const&, Foam::List<int> const&, Foam::refinementHistory const&) in "/home/jochem.vermeir/OpenFOAM/OpenFOAM-1.6.x/lib/linux64GccDPOpt/libdynamicMesh.so"
#4 Foam::meshRefinement::meshRefinement(Foam::fvMesh& , double, bool, Foam::refinementSurfaces const&, Foam::shellSurfaces const&) in "/home/jochem.vermeir/OpenFOAM/OpenFOAM-1.6.x/lib/linux64GccDPOpt/libautoMesh.so"
#5 main in "/home/jochem.vermeir/OpenFOAM/OpenFOAM-1.6.x/applications/bin/linux64GccDPOpt/snappyHexMesh"
#6 __libc_start_main in "/lib/libc.so.6"
#7 _start at /build/buildd/eglibc-2.10.1/csu/../sysdeps/x86_64/elf/start.S:116
Aborted


Can someone tell me what i am doing wrong?

I am doing this tutorial because i want to simulate air flow trough a build environment. I think i can do this just changing the water into air. Does someone thinks this i possible?


Regards,

Jochem
Jochem is offline   Reply With Quote

Old   May 13, 2010, 17:03
Default
  #2
Member
 
Alan Russell
Join Date: Aug 2009
Location: Boise, Idaho USA
Posts: 61
Rep Power: 7
AlanR is on a distinguished road
Jochem,

I think you have something wrong in your snappyHexMeshDict file settings causing the error. To simulate flow through a building, I would refer to the motorBike tutorial. It's a mesh tutorial, but it has all the settings for k-epsilon turbulence modeling of the motorbike in a wind tunnel. This is probably closer to what you're trying to do than changing fluids.
I think motorBike has an Allrun file, or you can run it with three solvers: blockMesh then snappyHexMesh, then simpleFoam.

Good luck,

Alan
AlanR is offline   Reply With Quote

Old   May 13, 2010, 17:09
Default
  #3
Member
 
Alan Russell
Join Date: Aug 2009
Location: Boise, Idaho USA
Posts: 61
Rep Power: 7
AlanR is on a distinguished road
You also have no refinement surfaces because the triSurface directory is empty. That's the directory where you put model geometry files in .stl format. After that, you need to call the .stl file in the snappyHexMeshDict file - there are four places that you need to update to properly link the .stl file. The snappyHexMeshDict file in the tutorials will give you good examples.

Alan
AlanR is offline   Reply With Quote

Old   May 14, 2010, 06:49
Default
  #4
New Member
 
Jochem
Join Date: May 2010
Posts: 28
Rep Power: 7
Jochem is on a distinguished road
Hi Alan,

First of all thanks for the tips and the quick response. I will try and run the motorbike tutorial. Probably you're correct if you say that it will be easier to just modify geometry instead of adjusting the fluid.

I still have one question about the bigWave tutorial. Do I have to insert a .stl file in the triSurface directory? I already set the geometry in the snappyHexMeshdict file like they say in the tutorial. Is this not enough to define the geometry?

Regards,

Jochem
Jochem is offline   Reply With Quote

Old   May 14, 2010, 13:32
Default
  #5
Member
 
Alan Russell
Join Date: Aug 2009
Location: Boise, Idaho USA
Posts: 61
Rep Power: 7
AlanR is on a distinguished road
The dictionary file tells the solver where to find the geometry file, but the actual file itself needs to be in the triSurface directory. From your first post, these statements indicate that the solver didn't fine any refinement surfaces:

Reading refinement surfaces.
Read refinement surfaces in = 0 s

Reading refinement shells.
Refinement level 1 for all cells inside refinementBox
Read refinement shells in = 0 s

Setting refinement level of surface to be consistent with shells.
Checked shell refinement in = 0 s

If it found a surface file, it would have taken some amount of time (> 0) to read and refine. I haven't looked at the bigWave tutorial, but I have spent a lot of time with snappyHexMesh. It works quite well once you get everything set up correctly - I spent a lot of time working on the setup...

Alan
AlanR is offline   Reply With Quote

Old   May 15, 2010, 08:43
Default
  #6
New Member
 
Jochem
Join Date: May 2010
Posts: 28
Rep Power: 7
Jochem is on a distinguished road
Alan,

Thanks for the explanation. I've runned the motorBike tutorial without any problems.

I will now try to use this tutorial to simulate the airflow along buildings.

Regards,

Jochem
Jochem 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
Tutorial for subcooled nucleate boiling Asghari FLUENT 34 September 27, 2013 04:58
Problem on Fluent Tutorial: Horizontal Film Boilig Feng FLUENT 2 April 13, 2013 05:34
SI engine tutorial error non-positive volumes rackem FLUENT 12 November 22, 2010 09:06
STAR-CD Tutorial shekhar aryal STAR-CD 4 March 22, 2010 04:25
Rotor/stator tutorial, and how to... gilberto CFX 5 January 21, 2002 10:41


All times are GMT -4. The time now is 02:12.