Hi, I have some question about simulate flow around a ship. My first question, how exactly modelling flow around ship? Now I am trying to simulate flow around ship. I have decided to remove parts of the ship that is on the water, so I only modelling parts of the ship that is in the water (under draft). My model immersed in the middle of domain fluid. Is this correct ? I'm trying to calculate force (lift and drag). My freestream is along X axis. I' ve got good values for drag (X axis), but I have bad results for lift (Z axis) , I' ve got very big value (it's about half from drag value). How to set BC for my model so value from lift goes to very small values ? any idea? Thank you very much for everyone in this forum.

The drag force calculations are OK. But lift forces calculations may not be required for the ship hull.

You may calculate the viscous drag forces theoritically using flat plate boundary layer theory for varying ship velocities and these values can be compared with the CFD predicted drag values.

At the inlet give the Turbulence dissipation as Zero and calculate Turbulence kinetic energy according to the ship velocity.This gives very close predictions with CFD.