Abstract
In order to investigate the duct effects on the flow coming into a propeller in a duct-propeller system, flow visualizations were conducted by an oil paint method combining 16 mm movie film recording. Two kinds of duct shapes, namely an accelerating type and a decelerating type were tested locating them in front of the propeller in open-water condition with a thin plate in the center plane of the propeller. A shot of the film was taken every 2 seconds and projection is made at the normal speed of 24 frames per second to see the phenomena in accelerated mode. It was confirmed that this method was very useful to see the process of peeling of the paint off the plate surface and of stream lines allowing for more detailed physical investigations of flows.
