[CIG-LONG] Density change at depth with temperature dependency

[Walter Landry]

nicolas riel <a.nicolas.riel at gmail.com> wrote:
> Hi all,
> I want to use ChangeAtDepth function that I saw in the source code. Where do I
> have to insert it in my code ?

I have never used it, so it may not work.  But I think you just need
to load it as a plugin by adding the lines

    "plugins":
    [
        {
            "Type": "Underworld_DensityChange",
            "Context": "context"            
        }
    ],

near the beginning, and then set the variables

  materialDensityChangeHeight
  materialDensityNewDensity
  materialDensityToChange

> I also would like to add a temperature dependency for the density.
> Do I need to modify the source code in order to do it ?

It is already implemented, but not documented.  Instead of specifying
the density, you can specify a density equation.  As in

        "viscous":
        {
            "Type": "RheologyMaterial",
            "Shape": "nonsphereShape",
            "densityEquation": "1.0+T-p",
            "alpha": "1.0",
            "diffusivity": "1.0",
            "heatingElements": [
                {
                    "Q": "1.0",
                    "lambda": "1.0"
                }
            ],
            "Rheology": [
                "backgroundViscosity",
                "storeViscosity",
                "storeStress"
            ]
        },

You can also use an equation for alpha.  The density and alpha
equations can depend on temperature (T) and/or pressure (p).  So you
could use this to get the effect of a density change at depth.

> PS: Walter do you have some news about running the code in parallel ?

Not yet.

Cheers,
Walter Landry