[aspect-devel] cylindrical rigid body rotation

Ian Rose ian.rose at berkeley.edu
Fri Feb 28 13:36:38 PST 2014

It would be fairly easy to remove the net angular momentum as Wolfgang
described, and I may end up doing that, though what I have at the moment
takes a different strategy.  Instead I explicitly construct rotation
vectors and project them out of the solution, i.e.

v' = v - (v \cdot ( \omega \times r)) (\omega \times r)

I don't know whether this or the angular momentum approach is preferable
(or if there is some fatal flaw to my approach),  maybe somebody has some
insight into that.

Eric, I'm attaching some code that does this which you are welcome to use
or not use (go ahead and share/edit/include if you like); it is not
extensively tested at the moment...

On Fri, Feb 28, 2014 at 6:02 AM, Timo Heister <heister at clemson.edu> wrote:

> > If the goal is simply to remove the rotation from the solution (i.e., to
> > eliminate the kernel of the operator), then it's enough to run the
> > computation of the rotational mode over the entire domain. I think Shijie
> > only presents the formula as a general case, but I don't read it as
> saying
> > that it should be applied to anything other than the whole mantle.
> The last paragraph hints at using it to get the net rotation of the
> lithosphere only.
> > Has someone already implemented something in this form?
> Ian has something along those lines (see his email).
> --
> Timo Heister
> http://www.math.clemson.edu/~heister/
> _______________________________________________
> Aspect-devel mailing list
> Aspect-devel at geodynamics.org
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