Description of ship motion and comparison of a real-time unified hydrodynamic model with free running tests in calm water and regular waves

摘要

Ship bridge simulators are well established in education practices ofseafarers and mariners. The use of simulators in research is ramping updue to the EU motivation towards Blue Growth, where the quantity andquality of offshore operations are evolving. There is a need of deeperunderstanding of ship motion in waves within hydrodynamics research.Simulators solve both the seakeeping and maneuvering problemssimultaneously in order to represent the ship response in real-time.Methods that solve both the seakeeping and maneuvering are referred toas unified models. This study will present and describe ship motion, incalm water and regular waves, as experimented in free runningmaneuvering model tests (Rabliås & Kristiansen, 2019) and willcompare the result of the model tests with simulations using the unifiedmodel; Fossen’s vectorial unified model (2005). Fossen’s model usesfrequency dependent hydrodynamic coefficients and solves ship motionin 6 degrees of freedom, and the fluid memory effects are computedusing ShipX (VERES).This study investigates the performance of a hydrodynamic simulationmethod in regular incident waves. The container carrier Duisburg TestCase (DTC) hull is considered. Model tests including Zig-Zag 20/20 andTurning Circle maneuvers were performed in the Ocean basin at SINTEFOcean in Trondheim, Norway. Simulation and experiments cover a rangeof wavelengths, approaching the vessel from different directionsincluding head seas, beam seas and following seas.Presentation and description of ship motion in waves is challenging.Appropriate tools are required. Polar scatters were used for describingship motion in waves. The comparisons show that simulation results arecomparable with model tests, however the digital ship is a different ship.