Numerical Solutions of Interaction Problem between Hull and Propeller of a Ship Considering the Effect of Free Surface

The present paper deals with the interaction problem between the hull and the propeller of a ship advancing at a constant speed on the still water surface. The Rankine source method has been employed in order to take into consideration the effect of the free surface on the hull and the propeller. The vortex lattice lifting surface method has been applied to the propeller. The interaction problem between the hull and the propeller has been solved numerically by an iterative procedure, starting from the Hess & Smith solution for the source distribution on the hull surface of the double model approximated ship as the basic flow. The effect of the interaction of the propeller has appeared on the closest hull surface as the pressure reduction and on the upper free surface as the increase of the wave just above the propeller. The calculated thrust deduction factor has showed a fairly good agreement with measured ones for 4 m and 6 m model ships.