Rotor sails are slender cylindrical structures mounted on ships that aid in propulsion through forces generated using the Magnus effect. Previous testing of rotor sails has been conducted at low Reynolds numbers, however on large transport ships, the Reynolds number can exceed 3.5 million. The objective of this study was to characterize the effects of Reynolds number, velocity ratio, and tip effects on aerodynamic loading of a single rotor at full dynamic similarity. Testing was conducted within a High Reynolds Number Test Facility (HRTF) at Princeton University, a world unique facility that can be pressurized at up to 3500 psi for operational Reynolds numbers to be achieved. Three different rotor sail models with varying aspect ratios and endplates were tested, revealing previously unknown aerodynamic behaviour of rotor sails.

The experiment successfully developed a proof of concept for testing rotor sail diagnostics at a field-relevant Reynolds number. The results from the testing determined that increasing velocity ratio lead to increased performance The effect of endplates were found to be the most impactful sail design characteristic as well, with larger endplates generating higher loads at higher velocity ratios. These tests served as an extremely useful validation dataset for rotor sail performance, in an effort to better study the positive environmental impact of rotor sails. Rotor sails have the ability to make a significant impact on decarbonization of the maritime industry, and through creating an aerodynamic model at full dynamic similarity, a strong foundation is laid for future research. The research group hopes to expand our understanding of rotor sail aerodynamics through further simulations and experiments at operational conditions. Additional testing into flow measurement and implementation of a pressure sensing system is planned to be implemented in the future.