A chimera Reynolds-Averaged Navler-Stokes (RANS) method has been developed for time-domain simulation of transient flow induced by a ship approaching a berthing structure. The method solves the mean flow and turbulence quantities on embedded, overlapped, or matched grids. The unsteady RANS equations were formulated in an earth-fixed reference frame and transformed into general curvilinear, moving coordinate systems. A chimera domain decomposition technique has been employed to accommodate the relative motion between different grid blocks Kinematic and dynamic free surface boundary conditions were applied on the exact free surface to ensure accurate prediction of the water cushion between the ship and the berthing structures. Calculations have been performed for a two-dimensional ship hull form in lateral motion to demonstrate the feasibility of the chimera RANS approach for time-domain simulation of the hydrodynamic coupling between the ship and berthing structures. The numerical solutions successfully captured many important features of the transient flow around a berthing ship including the underkeel flow acceleration, wake flow separation, and water cushion between the ship and harbor quaywall.
Berthing damage can result in substantial economic and operational penalties. Even m a well executed berthing, a large ship possesses enormous kinetic energy that could seriously damage the berthing structure as well as the ship itself. Fender systems are provided at a berth to absorb the kinetic energy of the berthing ship and to mitigate Impact forces The amount of the energy to be absorbed and the maximum Impact force are the prevailing criteria for fender system design. However, due to the complexity of the berthing process, which involves structural and fluid coupling between the ship, fender system and surrounding water, a reliable and accurate assessment system for computing berthing energy has yet to be developed.
