[CIG-MC] SUPG method in CitcomS

[Jed Brown]

On Fri, Apr 6, 2012 at 22:20, Matthew Knepley <knepley at mcs.anl.gov> wrote:

> Can't you also do WENO reconstruction on an FEM solution?
>

It's much less natural and rarely done in practice.


> Okay, that was not how it was explained to me. Is it like a Laplacian
> filer (which would sharpen edges)? I don't see how this would reduce
> oscillation,
> although I guess it could result from the solve for the conservation
> requirement.
>

Look at the algorithm, it is a discrete interface sharpening filter.

http://www.agu.org/pubs/crossref/1993/92JB02858.shtml

It clips values that are greater than 1 or less than 0, tracking the
maximum over/undershoot. Values inside the bounds of that over/undershoot
are then pressed out to 1 and 0 respectively. Then the remaining
conservation error is distributed to all cells that are not identically 0
or 1. I don't see any way that this is sensible for thermodynamics.
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