In recent years, ship owners and shipyards need more energy-saving vessels by the regulation of SOx and EEDI (Energy Efficiency Design Index). Therefore, main shipyards are already equipped with ESDs (Energy Saving Devices) in front and behind the propeller, such as a stern duct and a rudder bulb. However, there are almost no research examples of the interaction of propellers with ESDs, and there is a possibility of improvement of propulsion performance by consideration of the interaction.
The self-propulsion test results with the stern duct and rudder bulb showed almost the same effect as adding the energy-saving effect of each ESD, and the highest energy-saving effect compared with bare hull was 15.0%. Also, due to the propeller position and pitch distribution, BHP (Brake Horse Power) difference of a maximum of 4.9% occurred. The PIV (Particle Image Velocimetry) measurement results confirmed that the flow field in front and behind the propeller changed depending on the propeller position and pitch distribution, and the interaction of propeller with ESDs also changed.
In this paper, the authors described model test results to investigate the interaction of propellers with ESDs for achievement of highest efficiency of propulsion devices.
