[CIG-LONG] Isostatic stress

[Nicolas.Riel]

Hi again,

Finally I resolved my problem.

To fix isostatic issues, I first run my model with viscous rheologies
and velocities = 0 for left, *bottom* and right boundaries.

Once the model is equilibrated (1Ma later), I look at the pressure max. and
set the isostatic stress at this value. Then I set the boundary velocities
and the non-newtonian rheologies at wanted values and restart the model at
the last checkpoint.

Hope this can help the community,

Cheers

Nicolas





On Thu, Feb 28, 2013 at 2:41 PM, Nicolas.Riel <a.nicolas.riel at gmail.com>wrote:

> Hi everyone,
>
>
> I have a little problem using the isostatic stress on the bottom boundary
> conditions. I'm modeling continental subduction with geothermal gradient,
> so I calculate the maximum pressure at the bottom of my model with an
> integrated equation (depending on the gravity, the thermal gradient, the
> thermal expansivity and the density of every layers) and use it as the
> bottom isostatic stress.
>
> However when I use this value  either the material flow out or flow in too
> fast (by several order of magnitude).
>
>
> Consequently, I set the value manually and step by step to find the
> appropriate isostatic stress (that can be very long).
>
> However I cannot find a way to determine it precisely by calculation,
> though It was perfectly working with Gale 1.6.1.
>
>
> I'm wondering how the pressure is calculated in Gale 2.0.1 and if there is
> a way to calculate it precisely ?
>
>
> Than you in advance,
>
> Nicolas
>



-- 
Nicolas RIEL
PhD
Institut des Sciences de la Terre
(ISTerre-UMR CNRS/UJF 5275) Maison des Géosciences
1381, Rue de la Piscine
38400 - Saint Martin d'Hères

http://nicolas.riel.free.fr
Mob. : 33.(0)6.65.58.97.99
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