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| Titel |
A fictitious domain method for fluid/solid coupling applied to the lithosphere/asthenosphere interaction. |
| VerfasserIn |
Nestor Cerpa, Riad Hassani, Muriel Gerbault |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250091838
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| Publikation (Nr.) |
 EGU/EGU2014-6152.pdf |
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| Zusammenfassung |
| A large variety of geodynamical problems can be viewed as a solid/fluid interaction problem
coupling two bodies with different physics. In particular the lithosphere/asthenosphere
mechanical interaction in subduction zones belongs to this kind of problem, where the
solid lithosphere is embedded in the asthenospheric viscous fluid. In many fields
(Industry, Civil Engineering,etc.), in which deformations of solid and fluid are "small",
numerical modelers consider the exact discretization of both domains and fit as well as
possible the shape of the interface between the two domains, solving the discretized
physic problems by the Finite Element Method (FEM). Although, in a context of
subduction, the lithosphere is submitted to large deformation, and can evolve into
a complex geometry, thus leading to important deformation of the surrounding
asthenosphere.
To alleviate the precise meshing of complex geometries, numerical modelers have
developed non-matching interface methods called Fictitious Domain Methods (FDM). The
main idea of these methods is to extend the initial problem to a bigger (and simpler)
domain.
In our version of FDM, we determine the forces at the immersed solid boundary
required to minimize (at the least square sense) the difference between fluid and
solid velocities at this interface. This method is first-order accurate and the stability
depends on the ratio between the fluid background mesh size and the interface
discretization.
We present the formulation and provide benchmarks and examples showing the
potential of the method : 1) A comparison with an analytical solution of a viscous flow
around a rigid body. 2) An experiment of a rigid sphere sinking in a viscous fluid (in
two and three dimensional cases). 3) A comparison with an analog subduction
experiment.
Another presentation aims at describing the geodynamical application of this method to
Andean subduction dynamics, studying cyclic slab folding on the 660 km discontinuity, and
its relationship with flat subduction. |
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