[FLASH-USERS] ensuring div B = 0 when adjusting evolution
Klaus Weide
klaus at flash.uchicago.edu
Wed Jun 7 15:04:00 EDT 2017
On Wed, 7 Jun 2017, Slavin, Jonathan wrote:
> Well I see your point about the declaration of dt in Simulation_interface.
> I will look at implementing my (currently working) solution in the Heat
> unit. One issue could be that the call of Driver_computeDt calculates
> various dt's. I believe that it would not set dt below dtmin. Currently I
> use dtinit as mentioned, which is smaller than dtmin, since the state after
> the explosion is initiated involves such large gradients. Of course the
> timestep quickly gets increased, but the single short timestep may be
> what's necessary to avoid numerical errors.
Jon,
I wonder why you think you need to use a dtmin greater than dtinit.
Generally dtinit should be so chosen so small that the time step actually
taken does not depend on it. If some physics unit requests a smaller
timestep (via Driver_computeDt), you should not normally have to
(or want to) override it with dtmin.
Klaus
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