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[ICEM] HexaMeshing on a wedge

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Old   January 26, 2012, 18:10
Default HexaMeshing on a wedge
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Max
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Hey Y'all

Im trying to Hexa mesh a wedge in a duct flow. The duct is rectrangular. The wedge is a, well, a wedge. Geometrically, its a rectangle with a triangle, extruded in depth, like this

::::>

the leading edge has a fillet. small radius.

My Problem is now:

AutoHexa meshing crashes. But i can create a surface mesh which looks pretty good. Close around the wedge, the algorith uses traingles to compensate the node count.
Still it crashes.

So i tried blocking. Problem here: the edge connection. If i set a count to the leading edge fillet (like 5, approx), i cant change the count on the way longer trailing edge. even if i turn off copy, the edges are matched. is there a way around this?

same if i have like 100 nodes around the pipe wall, i need to have the same 100 on the corresponding wedge. which leaves one too coarse or the other one too fine.
so is there a way to use blocking and also change mesh count over a surface?

cheers
max
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Old   January 27, 2012, 03:03
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Can you provide any pics or blk/tin file?
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Old   January 27, 2012, 04:06
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Use Y-Blocking. >>>>>> Create O-Block and select two edges and apply, you will get Y-Blocking.
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Old   January 27, 2012, 09:51
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create the oblock just around the wedge? and which edges for y?

attached the tin

cheers
max
Attached Files
File Type: zip hexdem2.zip (26.2 KB, 14 views)
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Old   January 27, 2012, 11:17
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Use the option quarter of O-grid (blocking -> Create Block -> From Vertices/faces : 3D and Quarter O-Grid as block type);

The blocking is attached.
Attached Files
File Type: zip WEDGE.zip (45.6 KB, 28 views)
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Old   January 27, 2012, 17:01
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Wedge with quarter o blocking (Y-block)

First two pics show the y-block created from hexa single block by selecting the top and bottom face and two edges on each face in O-blocking panel. Last two pics show the blocking after some working and the mesh for wedge .



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Old   January 27, 2012, 17:15
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Complete procedure





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Old   January 30, 2012, 10:26
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Thank you so much, that is pretty good.
Did you find a way to "disconnect" the edge relation or is this just not possible with the (fixed indexing) blocking?
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Old   January 30, 2012, 10:52
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In blocking you need one-to-one correspondence in corresponding edges, otherwise you shall be not able to mesh them.
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Old   February 2, 2012, 10:59
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Sorry guys I have to get it up again. Found a way for a decent mesh. Not exactly how you showed me, but turned out ok.

But I've got another small problem: I use Ogrids on the wedge and the pipe. That creates a really short corresponding edge inside the volume, reproducing all the boundary layer nodes again. I attached a zip with my blocking and pictures from a cut plane. I hope you can see what Im talking about. Is there a way to fix this?

Also, as soon as the mesh is converted to Unstruct and I try smoothing, it's just not going. Let it run for a whole night (10 iter) and nothing happend...

Best Regards
Max
Attached Images
File Type: jpeg dem wedge mesh1.jpeg (61.7 KB, 39 views)
File Type: jpeg dem wedge mesh2.jpeg (66.5 KB, 33 views)
File Type: jpeg dem wedge mesh3.jpeg (50.0 KB, 36 views)
Attached Files
File Type: zip hexdem2ogridunstruct.zip (55.9 KB, 9 views)
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Old   February 6, 2012, 16:03
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no one i cant figure out how to get rid of that and the high growth ratio is bad..
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Old   February 7, 2012, 00:11
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which edge you are talking about, can you please mention the no of that edge. Make your question more clear and you have also not included the suggestions made by BrolY

Last edited by Far; February 7, 2012 at 00:28.
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Old   February 7, 2012, 09:50
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I didnt because it wasn't working exactly how i wanted it, or lets say i found a way making the far field mesh more smooth.

I found out how it works. Add the right edges and it goes away. The documentation on Ogridding is bad
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