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AMReX-Astro / Castro

Castro (Compressible Astrophysics): An adaptive mesh, astrophysical compressible (radiation-, magneto-) hydrodynamics simulation code for massively parallel CPU and GPU architectures.
http://amrex-astro.github.io/Castro
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3D wdmerger problem should only simulate z > 0 #173

Closed maxpkatz closed 6 years ago

maxpkatz commented 7 years ago

The z-axis should use a lower reflecting boundary condition. This will halve the computational cost. It will also guarantee symmetry in the vertical direction; this symmetry is not guaranteed otherwise and the WD system tends to drift away from the z = 0 plane during a simulation due to numerical error.

maxpkatz commented 7 years ago

This is a work in progress on the branch wdmerger_half_domain.

At present there are some issues. The relaxation depends on summing up all the non-rotational forces on the domain, and then calculating the needed rotational force to balance them. If we do a symmetry boundary at z = 0, we need to be able to account for the forces that would have existed had we simulated the fluid on the other side. But the different forces reflect about that plane differently, so there's no obvious way to do that.

Also, the gravitational wave strain calculation needs to be updated for the symmetry as well.

maxpkatz commented 6 years ago

Closing as wontfix for now. This may still be possible, but currently does not seem worth the effort.