[CIG-LONG] tracking sedimentary layers during deformation

[Tristan Salles-Taing]

Hi all,

I am working on the coupling between Gale and a surface process model
(Sedsim).
The goal is to use Gale to deform the sedimentary layers which are deposited
with Sedsim.

To couple the two codes, I start with few time steps of Gale. Then use the
top surface evolution during these time steps as input to launch Sedsim.
Sedsim handle deposition/erosion of various
surface processes. When Sedsim reaches the simulated time of Gale, it stops
and I export the Sedsim sedimentary layers in Gale. Then restart Gale with
the added layers. And so on ...
To do so I made few modifications in Gale :
 1- minor changes on the surfaceAdaptor function which could handle now
various types of surface grids (was 1000x1000 only before)
 2- add a new shape function: SurfaceShape that works a bit like the
PolygonShape one. You specify your bottom and top surfaces in your xml input
and
     the rheology and yielding of the swarm particles between these
surfaces.

For the moment Gale is not able to restart from a considered time step such
as Underworld so the material characteristics are lost between two starts
but Guillaume Duclaux (CSIRO such as me)
said that it will maybe be available in the next release. Then I will have
to see how I can restart a Gale simulation with additional materials
(consisting of Sedsim stacked sedimentary layers)...anyway
that's not the purpose of my mail.

First of all, if you are interested in the modifications I made how can I
send them to you (I suppose you want to check them so is it ok if I use
subversion) ?

Secondly, I still have some issues when I try to export the modified
sedimentary layers from Gale. I already lost a lot of precision when I
import the SurfaceShape from Sedsim to Gale due to the fact that
Gale is distributing the swarm particle randomly inside a cell. So there
isn't a perfect match between my SurfaceShape coordinates and the swarm
particles. Then at the end of Gale run, I am computing
new surfaces which delimitate the different particles layers after
deformation. These surfaces are used to find the new sedimentary layers
thicknesses. However the surface tracking is really poor mainly
because it relies on randomly located particles.

Is there a way of forcing a particle two be at a specific location (X,Y,Z)
and can I track this particle during Gale run ?
Do you think it is possible to create a function such as the SurfaceAdaptor
one for the layers? It will take the surfaces I gave in the SurfaceShape and
adapt them according to particles displacements. Then
I will just have to output these surfaces to get the sedimentary layers
thickness evolution due to Gale deformations.


Thanks for your help or comments...

Cheers

Tristan
_____________________________________________________
Dr Tristan Salles, Research Scientist
CSIRO - Earth Science & Resource Engineering
Predictive Geosciences Group
PO Box 1130, Bentley, WA 6102, Australia
26 Dick Perry Ave, Kensington, WA 6151, Australia
Ph: +61 8 6436 8779
_____________________________________________________
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