[FLASH-USERS] 2D Spherical and Cartesian Geometry

[Michiel Bustraan]

Hello all,


I have two things that I could really use some help with, and I haven't been able to figure it out by myself.


Firstly, I've been trying to run a simulation in 2D with a spherical geometry, but a few steps after starting the simulation the code crashes due to a negative dt.

I set the density and temperature constant in the simulation, and the velocity to 0, so nothing should be happening (just as a test case).

I'm attaching a plot of the density just before the crash. I'm guessing the problem lies in the grid somewhere, but I have no idea how to fix it.?


Have any of you encountered something like this before?


Secondly, and the reason I've been wanting to switch to a spherical geometry, is the results of simulating shocks in 2D using a Cartesian geometry.

I ran some simulations with a spherical shock (outward radial velocity from a dense region), and found that the shock doesn't develop the same way in 2D as it does in

3D Cartesian. The shock tends to move much faster, as if it is encountering less resistance or has too much kinetic energy.


Shouldn't it be possible to have a 2D Cartesian slice of a spherical outward shock? Are these issues simply due to the geometry or from an error in setting up the problem?


I would really love some help on this, since I've just been trying unsuccessfully to fix it on my own.


Kind Regards,

Michiel Bustraan
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