A question about XFlow boundary conditions
 

hi
i am using xflow to model the sloshing impact force on the roof of rectangular storage tanks, the positive peak force is true in comparison with the experimental results but the negative forces or Suction forces after the impact, have more values versus experimental amounts. and it seems water glue to the roof surface more than reality, why this happens? i used virtual moving boundary condition for walls with automatic wall model selected.

thanks