Going off your suggestion, I was getting the same divergence errors as before.

However, I've had to drop to 100 times less for my time step unfortunately. Good news is that it's stable now. Bad news is it now takes 100x longer to solve because of the time step drop.

I'm seeing my CFL number drop fairly steadily (started at 6e-1, after 150 timesteps it's down to 5e-2). Is it possible to raise the CFL number after a few iterations?

Going off that idea, any reason you can see that the variable time step method isn't available for my simulation right now? Because that would help out a lot for this.


Thanks for your help!