Maybe the basics of fluid simulation are working. At least, it's mass conserving, velocity tends to die out, need to tune things, deal with borders.
Trying to figure out what's going on, velocities collapse towards 0 very quickly. Not really the effect I'm going for.
mend
Narrowing in. Still need to fix mass going to less than 0 on reverse advection step, and fix border conditions.
Changing edge effects by just having forces bleed off.
Fixing problems with reverse advection causing masses to drop to less than 0. Still some rounding errors with the doubles, but for the most part, it seems to be working.
Woo! Actually seeing waves develop at this point. Next put, things like heat, fans, boundaries, etc.