Fouling effect on the resistance of different ship types

Considering that the ship hydrodynamic behaviours differ by the ship types and dimensions, the effect of biofouling on ship resistance can also vary with different ships. In this study, Unsteady Reynolds Averaged Navier-Stokes (URANS) based towed ship models were developed to simulate the roughness effect of biofouling on ship resistance. A container ship (KCS) and a tanker (KVLCC2), representing slender and a full hull forms, were modelled with various scale factors and speeds. The CFD simulations were conducted with several fouling conditions by embedding the roughness function of barnacles into the wall-function of the CFD model (i.e. modified wall-function approach). The fouling effects on the resistance components, form factors, wake fractions and the flow characteristics were investigated from the simulations. Significant differences were observed varying with the hull types, lengths (scales) and speeds of the ships and it was concluded that these differences are dominated by two parameters; relative roughness height and the roughness Reynolds number.