falling object in interdymfoam
 

Hi, everyone:
I am trying to simulate falling object in water using interdymfoam, as it includes gravity and dynamic foam both. I changed a little bit from floating object, make the whole domain filled with water and changed the density of the box so it is able to sink. The simulation looks fine at the beginning steps as the acceleration and velocity are similar to experimental results. However, after running to t=0.6, Co number suddenly jumped up and the simulation crashed (even I used adjustable time step). Another problem is that I have never seen obvious flutter of the box, which should happen during falling process. I will appreciate a lot if some one can help me about this problem.