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Dear Michael<br>
<br>
I believe Dr. Mark Behn at WHOI and Prof. Garrett Ito at U. Hawaii
have been making efforts to assess the importance of elasticity in
lithospheric dynamics. You may want to contact them.<br>
Also, to completely turn off elasticity, I think it is a better idea
to make a new plugin for purely viscous rheology than to tweak the
Maxwell rheology.<br>
<br>
Localization right at boundaries where vel BCs are applied is a
diagnostic symptom of a larger time step size than what it should
be. If dynamic time stepping worked properly, it wouldn't happen.<br>
It s0ounds like a bug that time steps are not constrained by maxwell
relaxation time.<br>
I'll look into it. It would be very helpful if you could send your
input file to me.<br>
<br>
Cheers,<br>
Eunseo<br>
<br>
<br>
On 7/23/2010 4:22 PM, Michael Kaplan wrote:
<blockquote
cite="mid:AANLkTimz4_p6=pWKEQYZ5WFr=2hW4juwk43KqJtr2f0E@mail.gmail.com"
type="cite">Hi,<br>
Im interested in exploring the effects of elasticity on
lithospheric dynamics and consequently am looking for a way to use
purely viscous, purely plastic, and visco-plastic rheologies in
SNAC. Also, to compare SNAC and GALE it would be helpful to use
the same rheologies. Using SNAC's Maxwell plug-in and setting
elastic moduli orders of magnitude larger than the viscosity is
problematic because it creates a very short maxwell relaxation
time, which SNAC enforces must be greater than the time step. <br>
Switching dtType from a constant time step to dynamic time
stepping allows the simulation to run, but produces seemingly
unreasonable results. It seems with dynamic time stepping that
only the first time step is less than the maxwell relaxation time,
with all later time steps unconstrained by the relaxation
timescale. For reasons that I dont understand, this seems to
create simulations for which all the deformation is localized to
the boundaries which have a non-zero kinematic BC. <br>
One solution I plan on testing is to create a new plug-in for a
purely viscous rheology, but any other solutions or comments would
be greatly appreciated.<br>
Thanks in advance for the help!<br>
<br>
-Michael Kaplan<br>
USC Geodynamics<br>
<br>
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<br>
<pre class="moz-signature" cols="72">--
=====================================
Eunseo Choi
Post-Doctoral Research Scientist
Lamont-Doherty Earth Observatory
305c Oceanography
P.O. Box 1000
61 Rt. 9W
Palisades, NY 10964-8000
<a class="moz-txt-link-freetext" href="http://www.ldeo.columbia.edu/~echoi">http://www.ldeo.columbia.edu/~echoi</a>
Phone: 845-365-8813 Fax: 845-365-8156
=====================================</pre>
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