[Nek5000-users] Representing Curved Side in any plane

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

Hi Markus,

Did you visualize this with VisIt and with the geometry
put out into (at least) the first .fld or .f file ?

Paul


On Mon, 29 Mar 2010, nek5000-users at lists.mcs.anl.gov wrote:

> Hi,
>
> I was looking into the midpoint feature and generated a cube (1 element, x, 
> y, z from 0 to 1) in prenek, then converted all edges to the midpoint 
> notation with prenek, and then manipulated one edge in the rea file. This is 
> the resulting curved side section:
>  ***** CURVED SIDE DATA *****
>        12 Curved sides follow IEDGE,IEL,CURVE(I),I=1,5, CCURVE
>  1  1  0.500000       0.00000       0.00000       0.00000 0.00000     m
>  2  1   1.10000      0.500000       0.00000       0.00000 0.00000     m
> .
> .
> .
> 10  1   1.00000     -0.500000      0.500000       0.00000 0.00000     m
> 11  1   1.00000       1.00000      0.500000       0.00000 0.00000     m
> 12  1   0.00000       1.00000      0.500000       0.00000 0.00000     m
>
> where edge 10 is supposedly not a straight line any more.
>
> When I run this in nek, however, the cube still comes out with straight 
> edges.
>
> Are there any other parameters I need to set?
>
> I checked out the most recent nek version and overcame compilation issues 
> with gcc-gfortran 4.4.3-4.fc12 from the fedora 12 repository.
>
> Thanks,
> Markus
>
>
> nek5000-users at lists.mcs.anl.gov wrote:
>> 
>> 
>> Michael,
>> 
>> I've only recently added general purpose midside-node support,
>> which puts a point in 3-space for any one of the 12 edges and
>> nek then fits a parabola to this.
>> 
>> I'll set up an example that demos this.  The feature has limited
>> support at the moment -- but does work in nek5000 and generates
>> correct geometry.
>> 
>> Depending on what you are after, there may be other ways to
>> generate the geometry.   One of my favorite techniques is to
>> project a given input geometry onto the desired surface.
>> 
>> 
>> Paul
>> 
>> 
>> 
>> On Sat, 27 Mar 2010, nek5000-users at lists.mcs.anl.gov wrote:
>> 
>> 
>>
>>  Hello Users,
>> 
>> 
>> 
>>
>>  My question is in regard to the curved side data section in the REA
>> file.  I know that the first 3 terms describe the side, element, and
>> radius, but there are several other numbers that are currently zero, and
>> then the letter C.
>> 
>> 
>>
>>  Background for the question: I have a situation where I would like to
>> curve an element edge in any plane. I know this is possible from
>> previous posts regarding a sphere.rea.
>> 
>> 
>>
>>  I know that with two points and a radius, that is enough to describe a
>> circle in a plane.  But lets say I have a side where 2 pts lie on the
>> XY plane, but the center of the circle is located on the YZ plane for
>> example... the question is how to represent this in the REA. In the REA
>> you just give the element side ( 2 pts ) and the radius, which does fix
>> the circle center but the plane that contains the center is not
>> fixed.  So what I am wondering is what the other numbers in this
>> section do...if you could say, give the center instead of the radius, or
>> give a third point with the other 2 pts in the element side to fully
>> define the circle and plane.
>> 
>> 
>>
>>  Also, Is it possible to curve the remaining 4 sides of the element
>> (edges 9, 10, 11, 12 that would be in the "z" direction) in the same
>> manner as edges 1-8? Thanks for any input on this matter!
>> 
>> 
>>
>>  Regards,
>>
>>  Michael Meador
>> 
>> 
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>> 
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