[Nek5000-users] Representing Curved Side in any plane

[nek5000-users at lists.mcs.anl.gov]

Hi Paul, 



We tried a few simple geometries with the new midpoint feature and did have 

some success, however we are also experiencing a new learning curve with the 

feature and thought you could shine some light on it. 



We tried with only one element and have been successful.  We then tried with 

many elements, including all midpoints in the curved side section, and we 

received the "vanishing jacobian" error. Next, we tried removing from the curved 

side section; internal edges. So, any midpoints on edges that were "interior" to the 

geometry.  My best way to explain this would be midpoints which lie on edges that 

 do not see a boundary (meaning the edge is shared by elements on all sides.)  This 

 left us with only midpoints on the outer surface of the geometry, which we were able 

to deform quite nicely. However, we did reach a threshold at which point 

we got the "vanishing jacobian" again. 



So this brings up two questions: 



1.   Is there no support for internal edges, meaning only midpoints on the surface 

of the geometry can be deformed? (If so, I think that is not an issue but good 

information to have). 



2.  Is there a threshold distance from the midpoint to the undeformed edge for it 

to work?  Markus ran a case where the following worked: 



10  1   0.75000     -0.090000      0.750000       0.00000       0.00000        m 
  9  3   0.75000     -0.090000      0.750000       0.00000       0.00000        m 



But, below did not.      

10  1   0.75000     -0.100000      0.750000       0.00000       0.00000       m 
  9  3   0.75000     -0.100000      0.750000       0.00000       0.00000       m 



Thanks for any insight you can provide with this and the new feature! 



Regards, 

Michael 

----- Original Message ----- 
From: nek5000-users at lists.mcs.anl.gov 
To: nek5000-users at lists.mcs.anl.gov 
Sent: Monday, April 5, 2010 10:17:21 PM GMT -06:00 US/Canada Central 
Subject: Re: [Nek5000-users] Representing Curved Side in any plane 




Hey Paul, 



Sounds great! And I think this is exactly what we needed! We will try it tomorrow. 



Thanks again, 

Michael 


----- Original Message ----- 
From: nek5000-users at lists.mcs.anl.gov 
To: nek5000-users at lists.mcs.anl.gov 
Sent: Monday, April 5, 2010 9:29:33 PM GMT -06:00 US/Canada Central 
Subject: Re: [Nek5000-users] Representing Curved Side in any plane 

Hi, I've just added the midside-node support to the current svn repo for nek. 



Sorry - I thought I had upgraded this in October but apparently had not committed to 

the repo then. Hopefully all should work -- I retested my original benchmark w/ this new 

version and it is functioning. Please let me know if this now works for you. 

You should be able to modify any one of the 12 edges. 



Paul 
_______________________________________________ Nek5000-users mailing list Nek5000-users at lists.mcs.anl.gov https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/nek5000-users/attachments/20100408/14e8255e/attachment.html>