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IDProjectCategoryView StatusDate SubmittedLast Update
0000116OpenFOAM[All Projects] Bugpublic2010-12-23 13:452011-01-04 11:24
Reporterwyldckat 
Assigned Tomattijs 
PrioritylowSeverityminorReproducibilityalways
StatusclosedResolutionno change required 
PlatformLinuxOSUbuntuOS Version10.04
Product Version1.7.x 
Target VersionFixed in Version 
Summary0000116: Strange behavior by snappyHexMesh in the "incompressible/simpleWindFoam/turbineSiting" tutorial
DescriptionsnappyHexMesh doesn't behave normally when running in 32bit Single Precision with the tutorial "incompressible/simpleWindFoam/turbineSiting". Attached is the first 1000 lines of the output made by snappyHexMesh. After 3 hours of execution, it generated a 50GB log file... and it didn't seem like it was going to end any time soon.

The output looks like debug output, but I wasn't able to see where the respective flag was in the case files.
Of all the tutorials that use snappyHexMesh, this was the only one with such a strange output in single precision.
Steps To ReproduceStart the OpenFOAM (latest 1.7.x) environment in 32bit Single Precision.
Build the "linuxGccSPOpt" architecture.
Make a copy of the tutorial "incompressible/simpleWindFoam/turbineSiting".
Run "./Allrun" in the copied folder.
Check the file "log.snappyHexMesh" moments after snappyHexMesh has started to see if you get a similar output to the one attached.
Break the execution of "Allrun", unless you want to waste disk space and electricity.
Additional InformationI didn't try the SP 64bit version, nor did I debug snappyHexMesh to verify where and why this happens.
TagsNo tags attached.
Attached Files? file icon log.snappyHexMesh_head [^] (75,588 bytes) 2010-12-23 13:45

- Relationships

-  Notes
(0000198)
mattijs (manager)
2010-12-23 14:33

This is a known problem. It has problems in single precision intersecting close to an edge or point or walking along a face.
Workarounds:
- shift/tilt your initial mesh slightly
- loosen the triSurfaceMesh intersection tolerance. See the commented out 'tolerance' in the sample snappyHexMeshDict in the snappyHexMesh source directory.
- use a 'searchableSurfaceWithGaps' instead of a 'triSurfaceMesh'. It refers to an underlying triSurfaceMesh but just perturbs any test with a given offset. You'll have to experiment a bit to get the settings.
(0000199)
wyldckat (reporter)
2010-12-23 14:49
edited on: 2010-12-23 14:49

So, there is no debug flag to disable this sort of output and simply leading snappyHexMesh to crash or something like that...

That's a whole lot of trouble, since I'm just developing a test bench for comparing tutorial results between Linux builds and MinGW builds. I guess this tutorial case will have to simply get blacklisted in SP mode.

Nonetheless, many thanks for the reply!


- Issue History
Date Modified Username Field Change
2010-12-23 13:45 wyldckat New Issue
2010-12-23 13:45 wyldckat File Added: log.snappyHexMesh_head
2010-12-23 14:33 mattijs Note Added: 0000198
2010-12-23 14:49 wyldckat Note Added: 0000199
2010-12-23 14:49 wyldckat Note Edited: 0000199 View Revisions
2011-01-04 11:24 andy Status new => closed
2011-01-04 11:24 andy Assigned To => mattijs
2011-01-04 11:24 andy Resolution open => no change required