[Hooman.Fa]

Hi everyone.
I've faced a really fatal error in my simulation. i'm working on a submarine with 16.4m model length on the surface of water (multiphase). I use dynamic mesh for 6-DOF and remeshing (local cell is enabled), layering (split factor=0.5 , collapse factor=0.2) and smoothing (spring constant factor is 1E-5 & number of iteration is 100) are enabled. also my mesh is concluded both structural mesh for far away the model and nonstructural near the submarine model (11724000 mesh elements). I have used a UDF code for 6-DOF to determine the model properties. The time step value is set to 1E-4. URF for pressure is 0.05 and in advanced solution controls for pressure I've used V-cycle with BCGSTAB stabilization method and for x,y,z momentum flexible termination is set.
after 70 time steps (3500th iteration) Negative volume cell detected.
can anyone help me please? I'm really stuck in a bad situation.
thank you so much.