A Numerical And Experimental Research On The Viscous Hydrodynamic Forces Acting On A Ship In Manoeuvring Motion

Accurate prediction of ship hydrodynamic performance at design stage using Computational Fluid Dynamics (CFD) technique has important value of engineering application in the ship industry. It is also a challenging subject in the field of ship hydrodynamics. With the rapid development of computational methods and computer technology, ship CFD is becoming a practical tool in ship design during the last decades. In this respect, it tends to be an alternative of towing tank tests. In the field of ship manoeuvrability, although this method is still in the primary stage of development, it has already achieved great progress. At present, the 25th ITTC manoeuvring committee is organizing a comparative research on ship manoeuvrability, and will organize a workshop on verification and validation of ship manoeuvring simulation methods based on this research. Under this background, the present thesis researches on the numerical computation of hydrodynamic forces and simulation of viscous flow around a ship in manoeuvring motion by means of CFD method.In this thesis, KVLCC2, one of the standard ship forms used in the comparative research is taken as the main object. Firstly, the numerical simulation of viscous flow around the KVLCC2 model in oblique motion in deep water is carried out. The lateral force, yaw moment, pressure distribution on the hull surface and the wake are calculated.As the size of ships develop to macro-scale, gulf, and canal, etc. have changed to restricted water. Due to the different in the motion and hydrodynamic forces, the manoeuvring of ship in shallow water is greatly different from that in the unrestricted water. For a ship traveling in shallow water, maritime disaster, such as collision, and grounding may occur more easily than in unrestricted water. Therefore, satisfying the criterion of the present IMO's standards for ship manoeuvrability can't guarantee the navigation safety. It is necessary to research the ship's manoeuvring ability in restricted water and to constitute corresponding manoeuvrability standards. Under this background, the lateral force, yaw moment, pressure distribution on the hull surface and the wake in shallow water are calculated and compared with those in deep water. The correction factors accounting for the effect of shallow water are determined.In order to take part in the comparative research mentioned above, cooperating with CSSRC, SJTU has carried out oblique towing test with KVLCC2 model in the towing tank of SJTU. The experimental results are given in this thesis. Compared with the experimental results, the computional results are verified.