Contributed by the Fluids Engineering Division for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received by the Fluids Engineering Division November 16, 2001; revised manuscript received April 12, 2004. Review conducted S. Ceccio.
All lifting surfaces that terminate in a moving fluid create tip vortices as a by-product. Tip vortices on marine propellers have two undesirable effects: they reduce the efficiency of the blade and they may cause tip vortex cavitation. Tip vortex cavitation can cause pitting and erosion of the propeller and surrounding equipment and is also a source of vibration and noise.
Several devices and methods have been studied to reduce the effects of tip vortices on propellers, including the Kort Nozzle, bulbous blade tips 1, porous blade tips 2, small bladelets 3, and injecting a dilute polymer solution at the tip of a hydrofoil 4 5.
This study focuses on ducted...
