DFBI: Lifeboat with Overset Mesh

This tutorial demonstrates use of the Overset Mesh feature with free surface flow and DFBI to model the motion of a lifeboat falling into water. Simcenter STAR-CCM+ automates the grid overlapping process.

The case is inspired by an experiment that is described in the paper “Simulation of Lifeboat Launching under Storm Conditions” by H.J. Morch et al. (2008). A lifeboat that is launched from a ramp undergoes linear and angular acceleration before hitting the water surface.



You model motion with three degrees of freedom: vertical and horizontal translation, and pitching rotation. This setup allows you to use symmetry conditions and include only half the geometry, thus reducing the computational cost of the simulation.

The full fall of the boat from rest on the ramp need not be modeled. Boat motion through the air can be pre-computed using simplified classical physics equations. The simulation is started with the boat initially positioned just above the water surface, with the following properties:

  • Mass: 10,000 kg
  • Moment of Inertia about axes passing through center of mass: 16000.0 kg m2
  • Initial downward velocity: 22 m/s
  • Initial angular velocity: 0 rad/s
  • Initial inclination: 35