[cig-commits] commit 2309 by bangerth to /var/svn/dealii/aspect
dealii.demon at gmail.com
dealii.demon at gmail.com
Mon Feb 17 19:18:04 PST 2014
Revision 2309
Discuss the 2d annulus cookbook.
U trunk/aspect/cookbooks/shell_simple_2d.prm
A trunk/aspect/doc/manual/cookbooks/shell_simple_2d/
A trunk/aspect/doc/manual/cookbooks/shell_simple_2d/depth_average_temperature.png
A trunk/aspect/doc/manual/cookbooks/shell_simple_2d/rms.png
A trunk/aspect/doc/manual/cookbooks/shell_simple_2d/x-movie0000.png
A trunk/aspect/doc/manual/cookbooks/shell_simple_2d/x-movie0008.png
A trunk/aspect/doc/manual/cookbooks/shell_simple_2d/x-movie1000.png
U trunk/aspect/doc/manual/manual.tex
U trunk/aspect/doc/manual.pdf
U trunk/aspect/doc/modules/changes.h
U trunk/aspect/source/geometry_model/spherical_shell.cc
http://www.dealii.org/websvn/revision.php?repname=Aspect+Repository&path=%2F&rev=2309&peg=2309
Diff:
Modified: trunk/aspect/cookbooks/shell_simple_2d.prm
===================================================================
--- trunk/aspect/cookbooks/shell_simple_2d.prm 2014-02-17 20:06:48 UTC (rev 2308)
+++ trunk/aspect/cookbooks/shell_simple_2d.prm 2014-02-18 03:18:00 UTC (rev 2309)
@@ -2,7 +2,7 @@
# manual for more information.
-Set Dimension = 2
+set Dimension = 2
set Use years in output instead of seconds = true
set End time = 1.5e9
set Output directory = output
@@ -12,7 +12,6 @@
set Model name = simple
subsection Simple model
- set Thermal conductivity = 4.7
set Thermal expansion coefficient = 4e-5
set Viscosity = 1e22
end
@@ -38,7 +37,6 @@
set Fixed temperature boundary indicators = 0,1
set Include shear heating = true
- set Radiogenic heating rate = 0
end
Added: trunk/aspect/doc/manual/cookbooks/shell_simple_2d/depth_average_temperature.png
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Index: trunk/aspect/doc/manual/cookbooks/shell_simple_2d/depth_average_temperature.png
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--- trunk/aspect/doc/manual/cookbooks/shell_simple_2d/depth_average_temperature.png 2014-02-17 20:06:48 UTC (rev 2308)
+++ trunk/aspect/doc/manual/cookbooks/shell_simple_2d/depth_average_temperature.png 2014-02-18 03:18:00 UTC (rev 2309)
Property changes on: trunk/aspect/doc/manual/cookbooks/shell_simple_2d/depth_average_temperature.png
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Added: trunk/aspect/doc/manual/cookbooks/shell_simple_2d/rms.png
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Index: trunk/aspect/doc/manual/cookbooks/shell_simple_2d/rms.png
===================================================================
--- trunk/aspect/doc/manual/cookbooks/shell_simple_2d/rms.png 2014-02-17 20:06:48 UTC (rev 2308)
+++ trunk/aspect/doc/manual/cookbooks/shell_simple_2d/rms.png 2014-02-18 03:18:00 UTC (rev 2309)
Property changes on: trunk/aspect/doc/manual/cookbooks/shell_simple_2d/rms.png
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Added: trunk/aspect/doc/manual/cookbooks/shell_simple_2d/x-movie0000.png
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Index: trunk/aspect/doc/manual/cookbooks/shell_simple_2d/x-movie0000.png
===================================================================
--- trunk/aspect/doc/manual/cookbooks/shell_simple_2d/x-movie0000.png 2014-02-17 20:06:48 UTC (rev 2308)
+++ trunk/aspect/doc/manual/cookbooks/shell_simple_2d/x-movie0000.png 2014-02-18 03:18:00 UTC (rev 2309)
Property changes on: trunk/aspect/doc/manual/cookbooks/shell_simple_2d/x-movie0000.png
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Added: trunk/aspect/doc/manual/cookbooks/shell_simple_2d/x-movie0008.png
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Index: trunk/aspect/doc/manual/cookbooks/shell_simple_2d/x-movie0008.png
===================================================================
--- trunk/aspect/doc/manual/cookbooks/shell_simple_2d/x-movie0008.png 2014-02-17 20:06:48 UTC (rev 2308)
+++ trunk/aspect/doc/manual/cookbooks/shell_simple_2d/x-movie0008.png 2014-02-18 03:18:00 UTC (rev 2309)
Property changes on: trunk/aspect/doc/manual/cookbooks/shell_simple_2d/x-movie0008.png
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Added: trunk/aspect/doc/manual/cookbooks/shell_simple_2d/x-movie1000.png
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Index: trunk/aspect/doc/manual/cookbooks/shell_simple_2d/x-movie1000.png
===================================================================
--- trunk/aspect/doc/manual/cookbooks/shell_simple_2d/x-movie1000.png 2014-02-17 20:06:48 UTC (rev 2308)
+++ trunk/aspect/doc/manual/cookbooks/shell_simple_2d/x-movie1000.png 2014-02-18 03:18:00 UTC (rev 2309)
Property changes on: trunk/aspect/doc/manual/cookbooks/shell_simple_2d/x-movie1000.png
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Added: svn:mime-type
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Modified: trunk/aspect/doc/manual/manual.tex
===================================================================
--- trunk/aspect/doc/manual/manual.tex 2014-02-17 20:06:48 UTC (rev 2308)
+++ trunk/aspect/doc/manual/manual.tex 2014-02-18 03:18:00 UTC (rev 2309)
@@ -4150,22 +4150,351 @@
examples below.
\item extit{What is the domain (geometry)?}
+ This question is easier to answer. To first order, the domains we want to
+ simulate are spherical shells, and to second order ellipsoid shells that can
+ be obtained by considering the isopotential surface of the gravity field of
+ a homogenous, rotating fluid.
+ A more accurate description is of course the geoid for which several
+ parameterizations are available. A complication arises if we ask whether we
+ want to include the mostly rigid crust in the domain and simply assume that
+ it is part of the convecting mantle, albeit a rather viscous part due to its
+ low temperature and the low pressure there, or whether we want to truncate
+ the computation at the asthenosphere.
+
\item extit{What happens at the boundary for each variable involved
(boundary conditions)?}
+ The mantle has two boundaries: at the bottom where it contacts the outer core
+ and at the top where it either touches the air or, depending on the outcome
+ of the discussion of the previous question, where it contacts the
+ lithospheric crust. At the bottom, a very good approximation of what is
+ happening is certainly to assume that the velocity field is tangential
+ (i.e., horizontal) and without friction forces due to the very low viscosity
+ of the liquid metal in the outer core. Similarly, we can assume that the
+ outer core is well mixed and at a constant temperature. At the top boundary,
+ the situation is slightly more complex because in reality the boundary is not
+ fixed but also allows vertical movement. If we ignore this, we can assume
+ free tangential flow at the surface or, if we want, prescribe the tangential
+ velocity as inferred from plate motion models. spect{} has a plugin that
+ allows to query this kind of information from the exttt{GPlates} program.
+
\item extit{How did it look at the beginning (initial conditions)?}
+ This is of course a trick question. Convection in the mantle of earth-like
+ planets did not start with a concrete initial temperature distribution when
+ the mantle was already fully formed. Rather, convection already happened
+ when primordial material was still separating into mantle and core. As a
+ consequence, for models that only simulate convection using mantle-like
+ geometries and materials, no physically reasonable initial conditions are
+ possible that date back to the beginning of Earth. On the other hand, recall
+ that we only need initial conditions for the temperature (and, if
+ necessary, compositional fields). Thus, if we have a temperature profile at
+ a given time, for example one inferred from seismic data at the current
+ time, then we can use these as the starting point of a simulation.
\end{itemize}
-units
-geometry
+This discussion shows that there are in fact many pieces with which one can play
+and for which the answers are in fact not always clear. We will address some of
+them in the cookbooks below. Recall in the descriptions we use in the input
+files that spect{} uses physical units, rather than non-dimensionalizing
+everything. The advantage, of course, is that we can immediately compare outputs
+with actual measurements. The disadvantage is that we need to work a bit when
+asked for, say, the Rayleigh number of a simulation.
-\subsubsection{Simple convection in a quarter of an annulus}
+\subsubsection{Simple convection in a quarter of a 2d annulus}
-\subsubsection{Simple convection in a spherical shell}
+Let us start this sequence of cookbooks using a simpler situation: convection in
+a quarter of a 2d shell. We choose this setup because 2d domains allow for much
+faster computations (in turn allowing for more experimentation) and because
+using a quarter of a shell avoids a pitfall with boundary conditions we will
+discuss in the next section. Because it's simpler to explain what we want to
+describe in pictures than in words, Fig.~
ef{fig:simple-shell-2d} shows the
+domain and the temperature field at a few time steps. In addition, you can find
+a movie of how the temperature evolves over this time period at
+\url{http://www.youtube.com/watch?v=d4AS1FmdarU}.%
+ ootnote{In YouTube, click on the gear symbol at the bottom right of the
+player window to select the highest resolution to see all the details of this
+video.}
+egin{figure}[tb]
+\includegraphics[width=0.32 extwidth]{cookbooks/shell_simple_2d/x-movie0000}
+\hfill
+\includegraphics[width=0.32 extwidth]{cookbooks/shell_simple_2d/x-movie0008}
+\hfill
+\includegraphics[width=0.32 extwidth]{cookbooks/shell_simple_2d/x-movie1000}
+
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