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[ANSYS Meshing] Non Sweepable bodies

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Old   October 31, 2012, 03:54
Default Non Sweepable bodies
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Shuvayan Brahmachary
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Hi everyone.

I am working on a geometry where I have a cube and inside of which there is a sphere (Cut material, i.e the sphere is hollow). Now the problem stands that i can't create the sweepable bodies (at least in the part where the cube has the sphere in it, but I can create the sweepable area outside the sphere). I need to create sewwpable bodies for the antire cube (minus the hollow sphere).

any suggestion???

Sphere inside a cube sliced in three planes mutually perpendicular.JPG

no sweepable bidoes.JPG

no sweepable biodies 2.JPG
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Old   October 31, 2012, 08:34
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The bodies you create are not sweepable because of the sphere you put in the center. I assume you have DesignModeler, so if you want to get a mesh like in the images below you need to split the geometry to help the mesher.

This is meshed with the Multizone method and will result in the same kind of mesh that you get in ICEM hexa. I have also attached the project file where the mesh is created. Hope it helps.

https://www.dropbox.com/s/7oo40wpif7...be_sphere.wbpz


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Old   October 31, 2012, 09:15
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Thanks a lot man.. you are a real jem. It was the thing I have been trying for days now and thanks to you I finally have the solution.


Really appreciate it. Thanks again
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Old   October 31, 2012, 09:26
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While working on your project file...I couldn't view the mesh like you showed in your second picture. What could be the possible reason??

thanks in advance
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Old   October 31, 2012, 09:31
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Select one of the bodies, right click and choose "hide body"
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Old   October 31, 2012, 10:33
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Thanks that worked out. But This is the new issue I am getting. Tetrahedron mesh in the inner sphere. DO you know the possible cause?? I want it hexahedron like you did.

The pic. is attached here

tetrahedron mesh for sphere but why.JPG
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Old   October 31, 2012, 10:39
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Did you get that with my file?
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Old   October 31, 2012, 11:52
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No yours file was just fine. I just followed your steps and made one by my own. I must have done some mistake. I'll go through it once more. But Thanks for the help.
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Old   November 1, 2012, 05:15
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Do youactually have a sphere body in there btw? If that's the case, just delete it
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Old   November 1, 2012, 06:31
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Okay. you mean to say i have to add the sphere like you did BUT slice material right??
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Old   November 1, 2012, 06:36
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Just saying that if you want to model flow around the sphere, you only need the wall, not the actual sphere. So yeah, slice the cube with the sphere but then delete or supress the sphere body when meshing. Not sure if that's your problem, but from your image it looks like you have a nice mesh around the sphere and then the sphere itself is meshed seperately with tet mesh. But maybe the image is fooling me
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Old   November 1, 2012, 07:55
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Alright...Let em explain my problem that I am trying to solve. I need a solid CUBE with a Hole (SPHERE). There will be an inlet (any face of cube) and outlet (opposite face of the cube) and in between there will be this sphere (as a hole). I was told to get very very fine mesh indeed (like you created the inflated layer) near the sphere wall (all Hex, none Tet)for studying the velocity profile.

I'm attaching few pictures clear the confusion. Can you help Please??

comparasion mine Vs. yours.JPG

non sweepable sphere.JPG
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Old   November 1, 2012, 08:00
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Your suggestion worked. I just deleted the internal sphere and its sweepable now. Thanks a lott
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Old   November 1, 2012, 08:02
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Either use my files and just alter the dimensions in designmodeler (you would need a bigger cube if that is supposed to be your entire fluid domain, since the sphere is relatively big. Will help get accurate reults in the simulation), or select all bodies except the 6 bodies surrounding the sphere, and surpress them.

Then you are left with a multibody part consisting of only these 6 bodies. The inner boundaries of these bodies will then represent the sphere.

EDIT: Ok good, no problem
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Old   December 16, 2012, 13:27
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Hi there!.

I owe a lot to you for the kind of help you have been. I was wondering if you could give me some suggestion for this problem which I have tried many times but it returns an error 255.

The geometry is same except that instead of a spherical hole inside I have a triangular hole with two flaps. I need to create structural mesh and I was able to do so by creating slices and multizone meshing but it shows error 255 at solver manager. Can you provide any suggestions? I am badly stuck for days.





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Old   December 19, 2012, 11:12
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Quote:
Originally Posted by b.shuvayan View Post
Hi there!.

I owe a lot to you for the kind of help you have been. I was wondering if you could give me some suggestion for this problem which I have tried many times but it returns an error 255.

The geometry is same except that instead of a spherical hole inside I have a triangular hole with two flaps. I need to create structural mesh and I was able to do so by creating slices and multizone meshing but it shows error 255 at solver manager. Can you provide any suggestions? I am badly stuck for days.
So you have successfully meshed this new geometry? When does the error message occur? Do a search for error 255 and you'll find it can be due to lots of things. Perhaps best to ask the question in the CFX forum, since it's clearly there you are having this new problem. Also, try to provide more information, eg solver output
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Old   December 23, 2012, 14:56
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HI.
The previous problem solver absoultely perfectly, in which you helped a lot.
But I am trying this new problem where everything is same, even the boundary conditions. But the difference lies in the fact that the spherical hole has been replaced with triangular hole ( of certain width ) and it has flaps on either side of the triangle as well. The triangle is situated at the centre of the solid cube and I need to model flow around the triangle.

I tried your method of multi zone meshing but dur to unsymmetric geometry (i.e the triangle, unlike sphere), I am not able to to do fine mesh (hehxa hedral elements), like you did in the previous problem (images available above).

So I want to know if there is a way to get hexahedral mesh by any other way for unsymmetrical bodies like this one??


thanks in advance :-)
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Old   December 23, 2012, 15:03
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Seems like quite a big change from the previous geometry (sphere). Can you share an image of the geometry?
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Old   December 24, 2012, 14:24
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Here is a link of the geometry.

https://www.dropbox.com/s/s4rb0d4iyj...PARADOX%20.igs
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Old   December 26, 2012, 03:55
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Hi there!

I am sending a JPEG format picture for the clear view of the geometry. Hope it helps :-)

Thanks in advance
Attached Images
File Type: jpg Geometry desc.JPG (43.9 KB, 52 views)
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