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CATEGORIES:Isaac Newton Institute Seminar Series
SUMMARY:3D Numerical Modelling of Compressible Coupled Mag
ma/Mantle Dynamics With Adaptive Mesh Refinement -
Timo Heister ()\; Juliane Dannberg (Texas A&\
;M University )
DTSTART;TZID=Europe/London:20160610T090000
DTEND;TZID=Europe/London:20160610T110000
UID:TALK66423AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/66423
DESCRIPTION:Juliane Dannberg (dannberg@math.tamu.edu)\, Ryan G
rove\, Timo Heister (heister@clemson.edu)
M
elt generation and migration are important process
es for the evolution of the Earth'\;s interior
and impact the global convection of the mantle.
While they have been the subject
of numerous investigations\, the typical time and
length-scales of melt transport are vastly differe
nt from global mantle convection\, which determine
s where melt is generated. This makes it difficult
to study mantle convection and melt migration in
a unified framework. In addition\, modelling magma
dynamics poses the challenge of highly non-linear
and spatially variable material properties\, in p
articular the viscosity.
Here
\, we present our extension of the community mantl
e convection code ASPECT\, which adds the equation
s of two-phase flow of melt and solid\, as an exam
ple for how these challenges can be addressed. Fir
st\, We will analyse well-posedness\, existence\,
and uniqueness of the problem. Then we will discu
ss the correct way to do a stable higher order fi
nite element discretization. Finally\, the resulti
ng linear system is solved with an iterated solve
r preconditioned by a Schur complement-based bloc
k preconditioner. We demonstrate that applying ada
ptive mesh refinement to this type of problem is p
articularly advantageous\, as the resolution can b
e increased in mesh cells where melt is present an
d viscosity gradients are high\, whereas a lower r
esolution is sufficient in regions without melt. T
ogether with a high-performance\, massively parall
el implementation\, this allows for high resolutio
n\, 3d\, compressible\, global mantle convection s
imulations coupled with melt migration.
W
e present benchmarks of our solver to confirm the
theoretical results\, and apply our software to la
rge-scale 3d simulations of melting and melt trans
port in mantle plumes interacting with the lithosp
here to show robustness and parallel scalability o
f the linear solver. Our model incorporates the in
dividual compressibilities of the solid and the fl
uid phase in addition to compaction\, and we demon
strate that including these effects can change mel
t volumes by more than 20%. Moreover\, we show how
including melting\, melt migration and freezing o
f melt in global convection models can influence c
onvection patterns and the distribution of chemica
l heterogeneities in the mantle.
Our model of magma dynamics provides a fra
mework for modelling processes on different scales
and investigating links between processes occurri
ng in the deep mantle and melt generation and migr
ation.
LOCATION:Seminar Room 1\, Newton Institute
CONTACT:INI IT
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