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-   -   makeAxialMesh issue (http://www.cfd-online.com/Forums/openfoam-meshing/71918-makeaxialmesh-issue.html)

feijooos January 19, 2010 21:56

makeAxialMesh issue
 
Hi,

I am having some trouble using the makeAxialMesh utitlity. I am hoping somebody can help me out...

When I run the testcase in the makeAxialMesh folder (axialCavity), I don't get an axisymmetric mesh (see attached picture, top view of mesh). This is before I ran the collapseEdges utility. When I hit checkMesh, I get 1 failed test. After using the collapseEdges utility (1e-5 180 as variables), the mesh is ok, but the mesh remains unchanged visually. Am I just making a stupid mistake or this a serious issue??

http://feijo.nl/mesh.png

Furthermore, this utility only seems to work in the "new" mode. When using the "old" mode I get a printStack error upon execution of the collapseEdges utility.

Any ideas are very welcome!

Thanks, Eelco

gschaider January 20, 2010 12:34

Quote:

Originally Posted by feijooos (Post 243116)
Hi,

I am having some trouble using the makeAxialMesh utitlity. I am hoping somebody can help me out...

When I run the testcase in the makeAxialMesh folder (axialCavity), I don't get an axisymmetric mesh (see attached picture, top view of mesh). This is before I ran the collapseEdges utility. When I hit checkMesh, I get 1 failed test. After using the collapseEdges utility (1e-5 180 as variables), the mesh is ok, but the mesh remains unchanged visually. Am I just making a stupid mistake or this a serious issue??

http://feijo.nl/mesh.png

Furthermore, this utility only seems to work in the "new" mode. When using the "old" mode I get a printStack error upon execution of the collapseEdges utility.

Any ideas are very welcome!

Thanks, Eelco

This behaviour is a feature, not a bug ;) It allows you to define a geometry where the center of rotation is not going through the patch. Is it possible that you set the offset-parameter to a non-zero value?

Bernhard

PS: but the mesh looks the way you want it in "old" mode before you do a collapseEdges?

feijooos January 20, 2010 12:46

Dear Bernhard,

Thanks for the reply. Aah yes you're right, the offset-parameter is a non-zero value. That was an easy fix.

I think I also found the error with the "old" mode. When the offset value in the dictionary is non-zero, I get a printStack error when running checkMesh, which does not go away when collapsing the edges. However, when the offset is set to 0, there is no printStack error.

Thanks,

Eelco

ps. The mesh looks the way i want it when I use the "old" mode.

ivan_cozza January 21, 2010 05:57

Hi Foamers,
is makeAxialMesh working under OF 1.6.x?
Thanks,
Ivan

gschaider January 21, 2010 07:35

Quote:

Originally Posted by ivan_cozza (Post 243268)
Hi Foamers,
is makeAxialMesh working under OF 1.6.x?
Thanks,
Ivan

I think that the 1.5 version should compile/run on 1.6. Havn't used it myself in a long time, but a colleague of mine does ;)

Bernhard

CYMa August 12, 2010 04:25

Hallo, Eelco

input the following lines in rotationDict and the axis will go though (0 0 0) along the direction
(1 0 0)
rotationVector (1 0 0);
originVector (0 0 0);

CYMa August 12, 2010 04:27

Hallo, Ivan Flaminio Cozza

It also works
under OF 1.6.x, at least on my machine.

flowAlways October 22, 2014 18:02

1 Attachment(s)
Quote:

Originally Posted by gschaider (Post 243187)
This behaviour is a feature, not a bug ;) It allows you to define a geometry where the center of rotation is not going through the patch. Is it possible that you set the offset-parameter to a non-zero value?

Bernhard

PS: but the mesh looks the way you want it in "old" mode before you do a collapseEdges?

Hello Bernhard,
Thanks for sharing the utility.

When I run the axialCavity test case I get 1 fail in checkMesh after doing makeAxialMesh.

Wedge patch frontAndBack_pos not planar. Point (0.005 0.065 0.00370765) is not in patch plane by 3.9962e-08 metre

I get the same fail again in checkMesh after doing collapseEdges (with minimumEdgeLength 1e-5 and maximumMergeAngle 180)

Can you please help me with this. Also when I view the mesh in paraFoam it does not look the way a collapsed face should appear(attahced image). Does it mean that its wrong ? Also I dont understand what makeAxialOldMode and makeAxialOffset do ?

gschaider October 23, 2014 05:21

Quote:

Originally Posted by flowAlways (Post 515631)
Hello Bernhard,
Thanks for sharing the utility.

When I run the axialCavity test case I get 1 fail in checkMesh after doing makeAxialMesh.

Wedge patch frontAndBack_pos not planar. Point (0.005 0.065 0.00370765) is not in patch plane by 3.9962e-08 metre

I get the same fail again in checkMesh after doing collapseEdges (with minimumEdgeLength 1e-5 and maximumMergeAngle 180)

Can you please help me with this. Also when I view the mesh in paraFoam it does not look the way a collapsed face should appear(attahced image). Does it mean that its wrong ? Also I dont understand what makeAxialOldMode and makeAxialOffset do ?

That is probably a problem with the precision of the point coordinates written to disc. You probably have a writePrecision of 6 in the controlDict. That means that there are digits truncated from the real coordinates which means that when checkMesh reads them in it looks like the point is not in the plane. Increase the writePrecision to 10 or higher before using the mesh manipulation utilities and afterwards reset it to the old value


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