2025S-OS4-3 Development of Windmill Sail

Abstract

To reduce GHG and fuelcosts, we introduce a new wind propulsion device called a “Windmillsail” that combines the characteristics of a rotor sail and a vertical axis wind turbine based on the concept of a “rotor sail that rotates with the force of the wind”. The shape of the windmill sail is designed to be rotationally symmetrical in order to ensure that they always move forward regardless of the wind direction. Inaddition, in order to maximize magnus force, the shape of the sail has multiple parallel wings. It has greater propulsive force than rigid-wingsails, and unlike rotorsails, it can generate electricity while propelling. The 2-D hydrodynamic analysis confirmed that the lift coefficient exceeds 5 and at the same time the power coefficient is about 0.25. This paper outlines the characteristics of windmill sails, their development to date, and a vision for the future.