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Re: PHAST question






> I don't know why, when using a small time step, I get oscillations.  The
smaller the time step the larger the oscillations. I would have thought,
due to the Courant conditions, the results would be more precise with a
smaller time steps.

I think it is because you are using centered in space. I'm not expert on
error analysis of numerical methods for finite difference, but I think
centered in space can lead to oscillations. I almost always use -space 0;
-time 1 to avoid this possibility. If you want to know more, I can ask Ken
Kipp to give us a thorough explanation.

David


David Parkhurst (dlpark@xxxxxxxx)
U.S. Geological Survey
Box 25046, MS 413
Denver Federal Center
Denver, CO 80225

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