[aspect-devel] Implementing a composite medium

[John Naliboff]

Hi Felipe,

I'm not sure I fully understand what features you would like in your 
model. When you say you "need the viscosities and mass-densities to vary 
by layer", do you mean that the viscosities and mass-densities should 
change at a fixed depth, as a function of composition (ex: whether or 
not a compositional field is present --> interface evolves through time) 
or a combination of these two types of behaviors?

The multicomponent material model allows you to specify different 
properties (reference density, viscosity, etc) for different 
compositional fields, but the properties are constant through time 
(e.g., not pressure or temperature-dependent viscosity, etc).

Other material models that use compositional fields ('diffusion 
dislocation' or even 'simple') have more complicated viscous flow laws. 
You can combine either of these with the 'depth dependent' material 
model, which simply modifies the viscosity as a function of depth 
(user-specified) after the viscosity in the other material models has 
been computed.

Cheers,
John
On 05/22/2018 11:17 AM, FELIPE ORELLANA ROVIROSA wrote:
>
>  Hi all,
>
>          I am trying to implement a layered medium in which the 
> material properties are composition- and temperature-dependent. More 
> precisely, I need the viscosities and mass-densities to vary by layer 
> (somehow by pressure-composition) and by temperature.
>
>          I tried doing this using the depth-dependent model, and the 
> depth dependence method = List, which only allows for viscosity 
> layering; and as a base model using the simple model, on which I 
> specified density differentials for compositional fields.
>
>           The model run for hours, no problem. When plotting the 
> results on Paraview, plotting the density field, I realized that the 
> model had NOT incorporated the density layering. More so, the system 
> evolution was basically the same as in previous models I had, which 
> consisted in temperature- and composition-dependent viscosity, but 
> temperature-dependent density only.
>           Somehow, the depth-dependence List is for viscosities only 
> (as the manual reads), but the material model Simple allows for 
> compositional fields with compositional densities.. But the whole set 
> didn't work as expected..
>
>            Would the 'multicomponent' model allow all these variations?
>
>            I keep reading the manual but I cannot find the proper way 
> to organize the code syntax, a parameter file implementation that 
> properly handles temperature- and composition-dependent densities and 
> viscosities.
>
>            I would appreciate some directions,
>
> cheers,
>
> Felipe
>
>
>
>
>
>
>
>
>
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