[blockMesh] blockMesh warning negative volume

pizzaspinate · January 13, 2015, 08:09

Hi guys,

I try to blockMesh my geometry but I get the following warnings when doing so:

FOAM Warning:
From function cellModel::mag (const labelList&, const pointField&)
in file meshes/meshShapes/cellModel/cellModel.c at line 128
zero or negative pyramid volume: -3.3333e+09 for face 1
FOAM Warning:
From function cellModel::mag (const labelList&, const pointField&)
in file blockMesh/blockMeshTopology.C at line 255
negative volume block: 0, probably defined inside out

What is the reason for this?
Where can I find meshes/meshShapes/cellModel/cellModel.c and blockMesh/blockMeshTopology.C?

Thank you very much in advance for your help

fertinaz · January 13, 2015, 08:30

would you share your blockMeshDict?

pizzaspinate · January 13, 2015, 08:32

uuupss, realised my mistake and solved the problem :-)

MaralMohajer · April 13, 2016, 10:11

Quote:

Originally Posted by pizzaspinate

uuupss, realised my mistake and solved the problem :-)

Hii

What was your mistake ?
I'm facing same problem .

Regardss
Maral

Antimony · May 15, 2016, 07:30

Hi Maral,

Check the order in which you have defined your vertices and the way you have called them while defining the hex block.

As an example, assuming that you are creating a cuboid, the way I would define it is to start at the lower z value, from the bottom left point and continue in a anticlockwise way to the top left point. And then do the same for the higher z value.

I have noticed that this way allows you to avoid the inside out problem.

Hope this helps.

Cheers,
Antimony

January 13, 2015, 08:09	blockMesh warning negative volume	#1
pizzaspinate Member Join Date: Dec 2012 Posts: 81 Rep Power: 13	Hi guys, I try to blockMesh my geometry but I get the following warnings when doing so: FOAM Warning: From function cellModel::mag (const labelList&, const pointField&) in file meshes/meshShapes/cellModel/cellModel.c at line 128 zero or negative pyramid volume: -3.3333e+09 for face 1 FOAM Warning: From function cellModel::mag (const labelList&, const pointField&) in file blockMesh/blockMeshTopology.C at line 255 negative volume block: 0, probably defined inside out What is the reason for this? Where can I find meshes/meshShapes/cellModel/cellModel.c and blockMesh/blockMeshTopology.C? Thank you very much in advance for your help Last edited by pizzaspinate; January 13, 2015 at 08:32. Reason: already solved problem

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January 13, 2015, 08:30		#2
fertinaz Member Fatih Ertinaz Join Date: Feb 2011 Location: Istanbul Posts: 64 Rep Power: 15	would you share your blockMeshDict?

January 13, 2015, 08:32		#3
pizzaspinate Member Join Date: Dec 2012 Posts: 81 Rep Power: 13	uuupss, realised my mistake and solved the problem :-)

May 15, 2016, 07:30		#5
Antimony Senior Member Join Date: Aug 2013 Posts: 407 Rep Power: 15	Hi Maral, Check the order in which you have defined your vertices and the way you have called them while defining the hex block. As an example, assuming that you are creating a cuboid, the way I would define it is to start at the lower z value, from the bottom left point and continue in a anticlockwise way to the top left point. And then do the same for the higher z value. I have noticed that this way allows you to avoid the inside out problem. Hope this helps. Cheers, Antimony