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Old   December 8, 2010, 09:45
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Robert Ong
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Hi,

I have a rather stupid question. When I type in snapEdge, it gives me an error message saying it can't read the designated stl file name. I'm sure the name of both the one in the snapEdgeDict and triSurface is the same. Sorry for posting up this question in this forum, as there is no other where else in the forum disccusing this matter.

Kind Regards,
Robert
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Old   December 8, 2010, 09:56
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Arne Stahlmann
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For snapEdge, the stl files must be in the main case directory (together with 0, system, constant etc.). So just create a link to the triSurface folder, or simply copy the stl files.
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Old   December 20, 2010, 18:51
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Hi,

amazing tool. I've been working with several "tricks" trying to solve the snappy problem with sharp edges... but only very specific and time consuming solutions!
I've been trying to download snapEdge.tgz for many hours w/o success from the openfoamwiki.net link (http://openfoam.nequam.se/cases/snapEdge.tgz). Is it a temporary problem or is there a new link or mirror somewhere?
Thanks in advance,
Gonzalo Tampier
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Old   December 21, 2010, 03:10
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Niklas Nordin
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The link is permanent.
Works fine for me.
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Old   December 30, 2010, 14:58
Default small orifice in a very large room
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Hello Niklas,

I am trying to use snappyHexMesh and snapEdge to insert a very small orifice (9mm diameter & 10 cm long) inside a very big room (20m L x 8 m H x 10 m W). My goal is to use dieselFoam to simulate water droplet distribution with incoming gas from the orifice (inlet) to increase the initial momentum of the droplets. Without the incoming gas, the initial/injection droplet velocity is about 6 m/sec. The incoming gas is about 340 m/sec. With the gas, the initial droplet velocity increases to about 160 m/sec. Improved momentum increases the distribution distance and area. I get this by placing the injector in front of the orifice/inlet. Basically, I combine your ammonium problem with aachenbomb.

I am new to all this snappyHexMesh and snapEdge, in particular, and OpenFOAM/dieselFoam in general. I have a few questions:

1) Is this a hopeless case since the orifice/inlet is sooo small as compared to the room dimensions that the mesh will never work out? Using checkMesh fails all the time.

2) What files after snappyHexMesh and snapEdge must I use to run the case?

3) Is there away to use dieselFoam solver and the injector to inject both gas and liquid at the same time? What must I modify if injecting both gas and liquid is possible?

Thank you for your help.

Nam
Attached Files
File Type: gz blockMeshDict.tar.gz (1.5 KB, 4 views)
File Type: gz cylinder.stl.tar.gz (32.7 KB, 5 views)
File Type: gz snapEdgeDict.tar.gz (1.2 KB, 17 views)
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Last edited by namCFD; December 30, 2010 at 17:03.
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Old   December 30, 2010, 15:04
Default Forget a file
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Oops, I forget to include the snappyHexMeshDict.
Attached Files
File Type: gz snappyHexMeshDict.tar.gz (3.5 KB, 7 views)
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Old   March 10, 2011, 16:40
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Daniel WEI (老魏)
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Great job! Thanks, Niklas.

Well, will snappyHexMesh next release includes your snapEdge feature?

I am meshing a building case, that is flow around building, and snapEdge works very good, though I still need help to improve the mesh quality.
mesh1.jpg
mesh2.jpg
mesh3.jpg
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Old   March 11, 2011, 02:39
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Quote:
Originally Posted by lakeat View Post
Well, will snappyHexMesh next release includes your snapEdge feature?
Nope, I would not recommend it either. Its by no means a finished product and it works
quite slow and only on 1 processor.
I am using it on a daily basis though for which it does exactly what I want and that is
to get a correct inflow/outflow area on pipe-flow simulations.
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Old   March 18, 2011, 12:21
Default snapEdge
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Hi Nikalas,
Have you ever tried to addlayers after using snapEdge. I feel like I have a problem adding layers after snapEdge. I don't have much experience with sHM but my aim is to create a mesh that captures the edge features well.
Problem
: After using snapEdge when I try adding layers, I see a very strange kind of behavior. Like some kind of baffles being created on surfaces and some sort of hanging cells. I was curious if anyone has seen you have ever seen this kind of behavior before and found any solution.
Regards,
Awais
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Old   March 18, 2011, 12:38
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Hmm, I forgot to report, that last time, a week ago, when I used snapEdge, and then, the simulation went wrong, floating points exaception, I think it is something related with snapEdge. But Im not sure
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Old   March 25, 2011, 13:40
Default SnapEdge and snappyHexMesh
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Hi

I am a new user of OpenFoam and am trying to generate a mesh for a slightly complicated geometry involving swirler blades.
I tried snappyHexMesh on the stl file, and it seemed to work fine; however, I am getting a floating point error with snapEdge.
The files are attached. Could someone more experienced look at it and suggest how I may improve the mesh (using both snappyHexMesh and snapEdge)?
I would like a coarser mesh (to reduce computation time), so perhaps snapEdge could be a useful tool.

Many thanks,
GK

[Edit: zip file modified]
Attached Files
File Type: zip OF_Trial.zip (51.7 KB, 8 views)

Last edited by usergk; March 25, 2011 at 18:51.
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Old   October 6, 2011, 16:45
Default snapEdge tested on OF 2.0.1?
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Has anybody tested snapEdge on OpenFOAM 2.0.1? I have a sparseimage distro on my Mac and have been happy with all functionality working. I'd like to check that snapEdge has been tested before risking mucking up my precompiled OF with a recompile...

Jan
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Old   October 6, 2011, 17:06
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Quote:
Originally Posted by jantheron View Post
Has anybody tested snapEdge on OpenFOAM 2.0.1? I have a sparseimage distro on my Mac and have been happy with all functionality working. I'd like to check that snapEdge has been tested before risking mucking up my precompiled OF with a recompile...

Jan
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You should not need to use snapEdge on OpenFOAM 2.x. The ragged edges bug is apparently fixed in snappyHexMesh now.

http://www.openfoam.com/news/snappyH...ature-edge.php
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Old   October 6, 2011, 17:52
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Quote:
Originally Posted by ziad View Post
You should not need to use snapEdge on OpenFOAM 2.x. The ragged edges bug is apparently fixed in snappyHexMesh now.

http://www.openfoam.com/news/snappyH...ature-edge.php
Hmmm.. I must be doing something wrong, for my stl file and the resulting openfoam grid after snappyHexMesh are quite different. I attached pics of both as well as my snappyHexMeshDict. Is there something obvious you can pick up?
Attached Images
File Type: jpg canoe_bow.jpg (75.6 KB, 69 views)
File Type: jpg canoe_stl.jpg (61.3 KB, 77 views)
Attached Files
File Type: txt snappyHexMeshDict.txt (10.8 KB, 9 views)
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Old   October 7, 2011, 03:42
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Hi Jan,

you can try the flange tutorial:

OpenFOAM-2.0.x/tutorials/mesh/snappyHexMesh/flange

Following lines are needed to capture sharp edges:


// Explicit feature edge refinement
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

// Specifies a level for any cell intersected by its edges.
// This is a featureEdgeMesh, read from constant/triSurface for now.
features
(
{
file "flange.eMesh";
level 0;
}
);

Then you have to run surfaceFeatureExtract before snappyHexMesh.

runApplication surfaceFeatureExtract -includedAngle 150 -writeObj constant/triSurface/flange.stl flange
runApplication snappyHexMesh -overwrite

Regards,
Stephane.
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Old   October 9, 2011, 03:20
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Johannes N Theron
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Stephane

Thank you! Lovely tip. Just one question: How would one visualize these edges that are produced?

Jan
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Old   October 9, 2011, 06:59
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Greetings to all!

@Jan: You can open the ".obj" files generated by surfaceFeatureExtract directly in ParaView, without any need for additional file conversion!

By the way, a thread where are already a few discussions about this new feature in OF 2.0 is this: http://www.cfd-online.com/Forums/ope...ture-edge.html

Best regards,
Bruno
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Old   October 9, 2011, 18:50
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Quote:
Originally Posted by wyldckat View Post
Greetings to all!

@Jan: You can open the ".obj" files generated by surfaceFeatureExtract directly in ParaView, without any need for additional file conversion!

By the way, a thread where are already a few discussions about this new feature in OF 2.0 is this: http://www.cfd-online.com/Forums/ope...ture-edge.html

Best regards,
Bruno
Thanks, Bruno

Worked like a charm!

Jan
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Old   July 23, 2012, 23:41
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Jongtae Kim
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Hello Niklas,

SnapEdge works for obj file.
It is interesting.

///////////////////////////////////////////
Hello Niklas,

Do you have any idea to use obj files instead of stl files?
Currently I have obj files only.
If you help me to modify the code, I would like to use it.

Many thanks.
Tj

Last edited by jkim; July 23, 2012 at 23:58.
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