Experimental and numerical investigation of ship resistance and free surface deformations

Prediction of ship resistance components in ship hull form design has a significant importance. Miscalculation of ship total resistance causes more fuel consumption which means an increase of the operating costs. In this thesis work, some numerical analysis based on the potential theory have been performed in order to form a basis to the investigation of wave deformations and wave resistance which is an important resistance component for particularly high Froude numbers. For this purpose, the wave deformations caused by a point source moving under free surface have been investigated by boundary elements method. Effects of linear and non-linear terms in the free surface boundary condition have been explored for different velocities and depths and a range of Froude number and depth is found in which non-linear results are in good agreement with the linear ones. In the study, total resistance, resistance components of a ship and wave deformations around a ship hull have been investigated experimentally and numerically. In this manner, firstly KCS is investigated for the validation of the numerical method and then detailed resistance and wave-cut experiments of a gas tanker (LNG) model have been carried out. For the same ship model, flow analyses are made with a computational fluid dynamics (CFD) procedure based on finite volume method in similar conditions. In CFD analyses, steady solutions are performed by using open channel method while the flow is turbulent. The resistance components and wave deformations gained from CFD are compared with the experimental ones and a good agreement in resistance components for Froude numbers (0.212Keyword: Akışkanlar mekaniği = Fluid mechanics ; Hidrodinamik = Hydrodynamics ; Sayısal akışkanlar dinamiği = Computational fluids dynamic