# [CIG-MC] I need a material model with depth dependent density (only).

Fri Jul 22 19:22:05 PDT 2016

You will need to modify the code. You can use these parameters to provide
reference_state=0
refstate_file=refstate.dat

The file refstate.dat will have nodez lines, and each line has 7 columns.
The meaning of the columns are:
rho, g, alpha, cp, not_used, not_used, not_used

You can modify the code to use one of the not_used column for your
depth-dependent \Delta \rho.

Regards,
--------

Assistant Research Fellow
Institute of Earth Sciences
http://www.earth.sinica.edu.tw/~tan2/tan2_e.html
Tel: +886-2-27839910 ext.503

On Fri, Jul 22, 2016 at 9:18 AM, Elbridge Gerry Puckett <
egpuckett at ucdavis.edu> wrote:

> Hi,
>
> I need a material model of the form
>
> \rho_0 + \Delta \rho + \rho_0 \alpha \Delta T    = if z < 0.5 D
>
> \rho(T) =
>
> \rho_0 - \Delta \rho + \rho_0 \alpha \Delta T     = if z > 0.5 D
>
> where D is the height of the domain.
>
> Note: The density in this model does NOT advect with the flow; i.e., we do
> not solve
>
> D \rho / D t = 0
>
> where D  / D is the material derivative.
>
> Furthermore, we DON'T want to use a compositional field or tracers.
>
> Do I need to write my own material model or is there one that will work.
>
> If I need to write my own, is the simple material model a better place to
> start than the depth dependent viscosity material model?
>
> Thanks!
>
> - G
>
>
>
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