[Nek5000-users] over-integration

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

The developers can correct me if I'm wrong here, but nek doesn't actually
use over-integration, although it does something similar (dealiasing).  If
we are computing, for example, u * u (u is vx in nek), the steps are :

1) Interpolate u to the higher space (given by lxd, lyd, lzd) (Nek has
arrays for this already...for velocity, they are vxd, vyd, vzd)
2) Compute the product ud*ud on the higher order grid
3) Interpolate the solution back to the original space (lx1,ly1,lz1)

I'm not aware of a mass matrix on the "dealiasing" mesh.

Josh


On Thu, Jan 24, 2013 at 3:13 AM, <nek5000-users at lists.mcs.anl.gov> wrote:

> Hello
> nek5000 can use over-integration for the quadratic nonlinear terms by
> setting lxd, lyd, lzd. Is it possible to use this for integration to
> approximate some integral like applying Biot-Savart law ? I have seen the
> use of the mass matrices bm1 and bm2 on the velocity and pressure meshes.
> Is there a mass matrix on the mesh (lxd,lyd,lzd) also which can be used for
> integration ?
>
> I have read about the use of over-integration as a stabilization method.
> Can you suggest some papers/books which discuss the theory behind this ?
>
> Thanks
> praveen
>
> _______________________________________________
> Nek5000-users mailing list
> Nek5000-users at lists.mcs.anl.gov
> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
>
>


-- 
Josh Camp

"All that is necessary for the triumph of evil is that good men do nothing"
-- Edmund Burke
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/nek5000-users/attachments/20130124/dedd6166/attachment.html>