I've been setting up a very small and simple FLIP sim using a couple of volume forces. I've encountered two issues: 1. I found as long as I tweak the time scale below 1, the simulation would just overflow (all the particles fly up). 2. The simulation is quite unstable after some frames, it'll create very unstable motions even I have a very smooth (without noise) volume force.I tried to set quite high surface tension and viscosity values but still couldn't solve the problem.
Benyee You can try to turn off the option "solver pressure with adaptivity" of the solver.
I have turned off solver pressure with adaptivity and the time scale works fine now! Thank you. But the simulation is still very unstable after a while. (I've been volume force to push the sim)