[MikePo]

Dear all,

I have been running some simulations on 2D aerofoils over the past few days and have developed an issue using the sample utility.

I require pressure and velocity distributions over the suction surface, and when using potentialFoam I ran sample specifying a surface. This seemed to work fine, however I am now running viscous models and due to the no-slip condition on the aerofoil surface I cannot sample a boundary, since I will just recover 0!

As a result I have attempted to run sample using a cloud distribution, some arbitrary distance away from the aerofoil surface. However, when I run sample, both on my case and on the tutorial airfoil2D, I receive the same error, printed below:

/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 1.6 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
Build : 1.6-53b7f692aa41
Exec : sample
Date : Feb 07 2010
Time : 18:25:16
Host : lark
PID : 9375
Case : /home/ug06/mjp106/FYP/2DAerofoilSimpleFoam
nProcs : 1
SigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh for time = 0



Badly formed bounding box: (-1.388 -0.701902 0.5) (-0.678599 0.00013911 0.5)#0 Foam::error:: printStack(Foam::Ostream&) in "/extra/local/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libOpenFOAM.so"
#1 Foam::error::abort() in "/extra/local/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libOpenFOAM.so"
#2 Foam::indexedOctree<Foam::treeDataPoint>::divide(F oam::treeBoundBox const&, Foam:: DynamicList<Foam::List<int>, 0u, 2u, 1u>&, int) const in "/extra/local/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libmeshTools.so"
#3 Foam::indexedOctree<Foam::treeDataPoint>::splitNod es(int, Foam:: DynamicList<Foam::indexedOctree<Foam::treeDataPoin t>::node, 0u, 2u, 1u>&, Foam: ynamicList<Foam::List<int>, 0u, 2u, 1u>&) const in "/extra/local/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libmeshTools.so"
#4 Foam::indexedOctree<Foam::treeDataPoint>::indexedO ctree(Foam::treeDataPoint const&, Foam::treeBoundBox const&, int, double, double) in "/extra/local/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libmeshTools.so"
#5 Foam::meshSearch::cellCentreTree() const in "/extra/local/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libmeshTools.so"
#6 Foam::meshSearch::findNearestCellTree(Foam::Vector <double> const&) const in "/extra/local/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libmeshTools.so"
#7 Foam::meshSearch::findNearestCell(Foam::Vector<dou ble> const&, int, bool) const in "/extra/local/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libmeshTools.so"
#8 Foam::meshSearch::findCell(Foam::Vector<double> const&, int, bool) const in "/extra/local/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libmeshTools.so"
#9 Foam::cloudSet::calcSamples(Foam:: DynamicList<Foam::Vector<double>, 0u, 2u, 1u>&, Foam:: DynamicList<int, 0u, 2u, 1u>&, Foam:: DynamicList<int, 0u, 2u, 1u>&, Foam:: DynamicList<int, 0u, 2u, 1u>&, Foam:: DynamicList<double, 0u, 2u, 1u>&) const in "/extra/local/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libsampling.so"
#10 Foam::cloudSet::genSamples() in "/extra/local/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libsampling.so"
#11 Foam::cloudSet::cloudSet(Foam::word const&, Foam:: PolyMesh const&, Foam::meshSearch&, Foam::dictionary const&) in "/extra/local/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libsampling.so"
#12 Foam::sampledSet::addwordConstructorToTable<Foam:: cloudSet>::New(Foam::word const&, Foam:: PolyMesh const&, Foam::meshSearch&, Foam::dictionary const&) in "/extra/local/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libsampling.so"
#13 Foam::sampledSet::New(Foam::word const&, Foam:: PolyMesh const&, Foam::meshSearch&, Foam::dictionary const&) in "/extra/local/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libsampling.so"
#14 void Foam::PtrList<Foam::sampledSet>::read<Foam::sample dSet::iNew>(Foam::Istream&, Foam::sampledSet::iNew const&) in "/extra/local/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libsampling.so"
#15 Foam::sampledSets::read(Foam::dictionary const&) in "/extra/local/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libsampling.so"
#16 Foam::sampledSets::sampledSets(Foam::word const&, Foam:: ObjectRegistry const&, Foam::dictionary const&, bool) in "/extra/local/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libsampling.so"
#17 Foam::IOOutputFilter<Foam::sampledSets>::IOOutputF ilter(Foam::word const&, Foam:: ObjectRegistry const&, Foam::fileName const&, Foam::IOobject::readOption, bool) in "/extra/local/OpenFOAM/OpenFOAM-1.6/applications/bin/linuxGccDPOpt/sample"
#18 main in "/extra/local/OpenFOAM/OpenFOAM-1.6/applications/bin/linuxGccDPOpt/sample"
#19 __libc_start_main in "/lib/i686/cmov/libc.so.6"
#20 _start at /usr/src/packages/BUILD/glibc-2.9/csu/../sysdeps/i386/elf/start.S:122


From function indexedOctree<Type>::divide(..)
in file lnInclude/indexedOctree.C at line 212.

FOAM aborting

Aborted

Secondly, which points should I sample at.. i.e. how far outside of the BL???

I would be grateful for all ideas, and am willing to provide elements of my case dir.

Many thanks!

[wyldckat]

Greetings Mike,

I'm not very skilled in doing sampling in OpenFOAM, but my guess is that you're bounding box should be 3D (since your simulation domain isn't pure 2D... check your settings in constant/polyMesh/blockMeshDict), even if your simulation is 2D. The other two possibilities that I can think of are:

• your sample box is too small and doesn't even get 1 cell;
• your sample box is outside the simulation space.

I would suggest checking the user guide, other tutorials and openfoamwiki.net for more ideas, just in case no one else answers

Best regards,
Bruno