[aspect-devel] Nonlinear solver scheme

[John Naliboff]

Hi Payman,

Typically the non-linear solver scheme is chosen based on the rheology 
and general processes you are trying to model, independent of the 
boundary conditions.  When using the 'visco plastic' material model I 
typically use the 'iterated IMPES' or 'iterated Stokes' non-linear solvers.

Trying the same model with each solver can be considered a good addition 
to a broader suite of sensitivity tests.  Likewise, testing how your 
results vary with the temperature polynomial degree is a good 
sensitivity test.  However, by default I typically use high-order 
elements for temperature/velocity/pressure/composition.

Hope this helps and when in doubt do lots of tests (preferably in 2D) to 
see how your model results vary with different parameters!

Cheers,
John

*************************************************
John Naliboff
Assistant Project Scientist, CIG
Earth & Planetary Sciences Dept., UC Davis

On 11/23/2016 10:17 AM, Payman Janbakhsh wrote:
>
> Hi
>
> For visco-plastic material model with fixed top surface , which non 
> linear solver scheme is recommended? Particularly in 3D where DOFs are 
> very large.
>
> To be more specific on where my doubts are I should say, to my 
> understanding velocity, temperature and viscosity are very much 
> influencing each other in this model. So I was thinking choosing a 
> scheme that solves temperature and velocity equations simultaneously. 
> Please correct me if I’m off the chart.
>
> As a second question, I know increasing temperature polynomial degree 
> increases accuracy. So is it recommended to have it at 3 or 2 is 
> sufficient for a viscoplastic 3D model.
>
> Thanks
>
> payman
>
>
>
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