Importance

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Abstract

A multi-bladed marine propeller designed for efficient operation in intermediate, partially cavitating flow regions between fully cavitating flow and noncavitating flow. Each of the blades has a radially inner subcavitating section and an outer section which is configured to have a higher angle of attack and tapered trailing and leading edges so that it supercavitates at high speeds either with or without ventilation and subcavitates at low speeds. Various other features of each blade include different length chords on the pressure and suction sides of the outer section and an inclined trailing surface area extending between the chord ends for improved off design, design point, and astern operation. A minimized transition area is included between the inner and outer sections, and narrow chord lengths are provided in the tip area to minimize and balance overall tip section drag. The supercavitating outer section also has positive rake to improve ventilation performance and positive skew to minimize undesirable transition flow. The result is a propeller with improved efficiency at low speeds without degrading the supercavitating section performance at high speed.

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First Claim