Re:_Re:_Re:_[MITgcm-support]_Advection_schemes

[samar khatiwala]

Petter,

This is a VERY long shot, but what version of the code are you using? In a
previous version, there was a bug in ptracers_advection.F. The line
involving multiDimAdvection was commented out. (This was fixed
a while ago, but I only discovered it recently in the checkpoint I was
using (c51h_pre).)

Samar

On Thu, 19 Aug 2004, Petter Stenström wrote:

> Hi Patrick,
>
> Thanks for your reply. Noop, I did not forget to specify
> tracerAdvScheme=33. The problem seems rather to be that multiDimAdv has to
> be false when using scheme no 33. I looked again in the documentation and
> found a note on that.
>
> The strange thing is that this seems to be required only for tr1, not for T
> and S. I ran a simple experiment in a simple domain with exactly the same
> initial distribution and concentration of T and tr1, and the same advection
> scheme (33). tr1 goes to infinity, whereas T stays on realistic values.
> Strange since tr1 seems to use the same diffusivity constants as T in the
> default configuration. I will look closer in the code and try to figure out
> what the difference between the two is.There are slight differences also
> when using other schemes (I've tried 3rd order upwind biased).
>
> /Petter
>
>
>
> ------- Original message -------
> From: heimbach at MIT.EDU
> Date: Wed, 18 Aug 2004 15:27:19 -0400
>
> Hi Petter,
>
> sorry I oversaw your reply
> (I am CC-ing to mitgcm-support and suggest
> that you always send to that list).
>
> Re. your question I think you forgot to also specify
>  tracerAdvScheme = 33
> in your data file.
> Can you try and see whether that gives the
> desired results?
>
> -Patrick
>
>
>
> Quoting Petter StenstrXm <petters at kth.se>:
>
> > Hi Patrick,
> >
> > thanks. 33 is apparently a flux limited 3rd order DST. It works fine with
> S
> > and T, but not with a passive tracer. I cannot understand why, but false
> > extrema appear in the TR1 field, but not in the S and T fields, when I use
> > 33 for all of them. Is there an obvious explanation for this that I don't
> > see?
> >
> > Petter
> >
> > ------- Original message -------
> > From: heimbach at MIT.EDU
> > Date: Tue, 17 Aug 2004 14:35:19 -0400
> >
> > Hi Petter,
> >
> > they are described in sections 2.16, 2.17
> > http://mitgcm.org/sealion/online_documents/node71.html
> > http://mitgcm.org/sealion/online_documents/node76.html
> > of the online documentation,
> > but for the actual number associated with each sheme
> > you'll have to look in the header file
> > pkg/generic_advdiff/GAD.h
> >
> > -Patrick
> >
> >
> >
> > Quoting Petter StenstrXm <petters at kth.se>:
> >
> > > Hi!
> > >
> > > Is there a list of all the different advection schemes available and
> their
> > > corresponding numbers? I cannot find any in the documentation.
> > >
> > > I have been using advection scheme 33 for some time (which I thought
> was a
> > > flux limiter scheme), but when I look now, I cannot see that the value
> 33
> > > is interpreted anywhere in the code.
> > >
> > > Regards,
> > >
> > > Petter Stenström
> > > Dept of Land and Water Res Eng
> > > Royal Institute of Technology
> > > SE-100 44 Stockholm
> > > Phone: +46 8 7908657
> > > Email: petters at kth.se
> > >
> > > _______________________________________________
> > > MITgcm-support mailing list
> > > MITgcm-support at mitgcm.org
> > > http://dev.mitgcm.org/mailman/listinfo/mitgcm-support
> > >
> >
> >
> > --------------------------------------------------------
> > Patrick Heimbach   Massachusetts Institute of Technology
> > FON: +1/617/253-5259                  EAPS, Room 54-1518
> > FAX: +1/617/253-4464             77 Massachusetts Avenue
> > mailto:heimbach at mit.edu               Cambridge MA 02139
> > http://www.mit.edu/~heimbach/                        USA
> >
> >
> >
> >
>
>
> --------------------------------------------------------
> Patrick Heimbach   Massachusetts Institute of Technology
> FON: +1/617/253-5259                  EAPS, Room 54-1518
> FAX: +1/617/253-4464             77 Massachusetts Avenue
> mailto:heimbach at mit.edu               Cambridge MA 02139
> http://www.mit.edu/~heimbach/                        USA
>
>
>
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