[rob3rt 0ng]

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

[Arnoldinho]

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.

[gtampier]

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

[niklas]

The link is permanent.
Works fine for me.

[namCFD]

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

[namCFD]

Oops, I forget to include the snappyHexMeshDict.

[lakeat]

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

[niklas]

Originally Posted by lakeat

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.

[owayz]

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

[lakeat]

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

[usergk]

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]

[jantheron]

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
www.kanoefabrik.com

[ziad]

Originally Posted by jantheron

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
www.kanoefabrik.com

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

[jantheron]

Originally Posted by ziad

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?

[openfoam_user]

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.

[jantheron]

Stephane

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

Jan

[wyldckat]

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

[jantheron]

Originally Posted by wyldckat

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
www.kanoefabrik.com

[jkim]

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