Development of numerical method to simulate flows around a ship at propulsion conditions in regular waves coupling with the ship propulsion plant model

A numerical method to simulate flows with propeller effects including the response of a ship propulsion plant has been developed. The dynamics of a ship propulsion plant is modeled by the function of the diesel engine control system. Propeller torque which is computed by the propeller model with the interaction to the flow fields is put into the ship propulsion plant model, then, the propeller rotational speed is obtained by solving the equation of the rotational motion of a propeller shaft line. Present method can reproduce the fluctuations of propeller rotational speed and torque in the condition with the regular head waves. The amplitude of fluctuations shows agreement with the measured data. The detailed analysis of the flow fields with ship motions which is difficult to be obtained at experiments is also carried out.