Experimental Investigation of Reynolds Number Effects on Marine Propeller Performance and Wake Development in a Compressed-Air Wind Tunnel

The study presents an experimental investigation of marine propeller operation at high Reynolds numbers in the Compressed-Air Wind Tunnel (CAWT) at Penn State. A wide range of Reynolds numbers is achieved by changing the pressure of the working fluid, enabling laboratory-scale reproduction of full-scale flow conditions up to a diameter-based Reynolds number (ReD) of 1.2 × 10⁶. The objective of this project is to quantify Reynolds number effects on propeller performance and wake structure. By analyzing wake characteristics such as velocity deficit and turbulence intensity across Reynolds numbers, the work establishes a benchmark dataset for high Reynolds number propeller operation while demonstrating a testing methodology capable of capturing full-scale wake physics in a controlled laboratory environment. Preliminary results revealed Reynolds number trends in both propeller's thrust and torque coefficients, with higher Re producing larger CT and CQ. The wake survey results follow these trends in both velocity profile and turbulence intensity in the wake region.