[CIG-LONG] Heat Flux BC and time dependent BC

[Walter Landry]

Edie Miglio <edie.miglio at polimi.it> wrote:
> Dear CIG,
>    I am using Gale and I would like to know if it is possible to
> impose a heat flux boundary condition when solving for the
> temperature. 

It is easy to get an insulating, zero heat flux, boundary condition.
Just do not specify anything on the boundary.  Non-zero flux is not
something that I know how to do right off the bat.  You can set a
boundary temperature, but not a boundary derivative.

> Moreover is it possible to use a stationary temperature equation ?

Do you mean solving for the temperature assuming that the time
derivative is zero, and thus turning the temperature equation into an
elliptic equation?  That seems to be implemented in Energy_SLE_Solver,
but I have not tested it.  You can look in 

  PICellerator/Apps/PIC_Components/DiffusionSolver.xml

for an example, though I do not know if it will work.

>    When solving the coupled problem (Stokes-temperature) is it
> possible to assign a time-dependent boundary condition for the
> velocity ?

Yes.  The Stepfunction StandardConditionFunction, for example, can be
a step function in space or time.  If you want to do something more
complicated, you have to implement it yourself, but it is not
difficult if you are already compiling the code.

>    Finally I have found that using the binary version I have some
> problem in imposing two different boundary conditions read from
> file: the code uses in both cases the BC read from File1. I have
> compiled the version obtained using the repository and everything
> works.

Yes, that is true.  I need to make a new release so that people do not
run into this problem anymore.

Cheers,
Walter Landry
walter at geodynamics.org