[aspect-devel] Far different velocity magnitudes & timestep sizes of the same Ra

[Wolfgang Bangerth]

On 04/24/2017 12:10 PM, Juliane Dannberg wrote:
> As far as I know we always use the full pressure (unless one chooses the
> density in the material model to only be the density deviations from the
> reference profile, in which case the computed pressure would be the dynamic
> pressure), and looking at the manual, I agree that we could document this better.

Yes, we use the full pressure. The full pressure, however, equals the dynamic 
pressure if you use a material model in which the density has no constant term 
and only contains the thermal expansion term, i.e.,
   rho(T) = -\alpha T
There is a hydrostatic component of the pressure if the density is given as
   rho(T) = rho_0 - \alpha T

Which of the two you use is up to you.

Best
  W.


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Wolfgang Bangerth          email:                 bangerth at colostate.edu
                            www: http://www.math.colostate.edu/~bangerth/