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Date et heure en ce moment : dimanche, 19 novembre 2017, 00:28

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Cassiopee Forum :: Discussions, suggestions, bug report :: Generator :: Surface extrusion  ::
Mikko
Newbie
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Messages: 2
Surface extrusion (mercredi, 18 janvier 2017, 22:36) citation  
Hi everyone,

In presentation elsa.onera.fr/Cassiopee/Citations/JSO2012.pdf on page 25/28 is a figure of a mesh around NACA0015. I wonder how was this 3D extruded mesh done? I cannot find any extrusion command from the user guide.

Best regards,
Mikko

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StephaniePeron
Full Member
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Messages: 158
RE: Surface extrusion (jeudi, 19 janvier 2017, 11:35) citation  
Hi,

Yes, it is not explicit in the name of the function. It is addNormalLayers function of Generator module.
In that case, I used 100 smoothing iterations to smooth normals at the trailing edge.

You can also use the tkCassiopee GUI 'cassiopee' : see the tutorial on top of this page : http://tiamat.onera/C/Main/UserGuides/Tutorials/Tutorials.html

the extrusion tool is in the 'Mesh' menu on the left and then you open 'tkExtrusion' applet.
There is a tutorial : http://tiamat.onera/C/Main/UserGuides/Tutorials/2DStructuredMeshing/2DStructuredMeshing.html

This provides a uniform extrusion, but you can modify the distribution of points a posteriori using tkStretch, enforce function in the 'k-direction' to refine in the boundary layer.

It is explained at the end of the same tutorial.
I hope this will be helpful and do not hesitate to contact us if you have any other question,
Regards
Stephanie

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Mikko
Newbie
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Messages: 2
RE: Surface extrusion (jeudi, 19 janvier 2017, 23:48) citation  
Dear Stephanie,

Thank you very much for your help! Cassiopee seems to be very powerful mesher. I really like the Python interface and also the GUI seems helpful.

Just a short followup, do you have plans to extend the hyperbolic extrusion also for surface meshes?

Best regards,
Mikko

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StephaniePeron
Full Member
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Messages: 158
RE: Surface extrusion (lundi, 23 janvier 2017, 10:45) citation  
Hi Mikko,

We have already a tool for surface extrusion : it is called surfaceWalk and it is also available in Generator.
Normals to the surface must be properly oriented, you can start from a curve lying on the surface. Direction of the extrusion is oriented similarly to the cross product l x n where l is the orientation of the curve and n the normals of the surface mesh.
You can also find an example and it can be found in the GUI in 'Surf', applet tkSurfaceWalk.
It is not actually an hyperbolic extrusion, it is a simple algebraic extrusion, with normal smoothing. Thus it can be less robust than hyperbolic extrusion.
Regards,
Stephanie

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