Practical application of viscous-flow calculations for the simulation of manoeuvring ships

The present work was initiated in order to improve traditional manoeuvring simulations based on empirical equations to model the forces and moments on the ship. With the evolution of the capability of viscous-flow solvers to predict forces and moments on ships, it was decided to develop a practical method to simulate the manoeuvrability of ships in which viscous-flow solvers are utilised and to investigate whether this improves the accuracy of manoeuvring predictions. In this thesis, it is demonstrated that good predictions of the loads on the hull in manoeuvring motion can be obtained for a wide range of ship types. The trends in the forces and moments as a function of the drift angle or yaw rate are simulated well. By using hydrodynamic manoeuvring coefficients derived from the CFD calculations, it is shown that it is possible to improve the prediction of ship manoeuvres compared to predictions using coefficients based on empirical equations. A considerable improvement in the turning circle predictions was obtained. The prediction of the yaw checking and course keeping and initial turning abilities based on zig-zag simulations improved as well, but further improvements are required for more reliable assessment of the manoeuvring performance.