Experimental Study on Wave Propulsion by an Oscillating Bow Fin

• Main Authors: Yu-Ting Hsu, 徐玉婷
• Other Authors: 邱逢琛
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/92050346738027155798

碩士 === 國立臺灣大學 === 工程科學及海洋工程學研究所 === 104 === Scientists have found that marine mammals like dolphins and whales swim in high efficiency. Marine mammals may also swim across the ocean by using wave energy and converting it to thrust through proper control of their tail fin. Ships traveling in wave will get ship motions from wave energy. It’s considered to be feasible to find an efficient way to enhance the ship propulsion by extracting wave energy and converting it to useful propulsive thrust. Hence, many concepts of propulsion system using active or passive control of oscillating fin are investigated and applied. However, most of them are focused on small crafts but not on general merchant ships. In the present study, a pair of oscillating bow fin with NACA0016 section controlled actively in pitch are applied to a container ship travelling in head waves for validating its effectiveness. The oscillating fins are placed underneath the front part of the container ship model with bulbous bow. The experiments implement in two wavelength of regular head wave, measure the mean speed of the ship model in wave with controlling the phase angle between heaving and pitching motion of the oscillating bow fin. The target of these experiments is to change the phase angle between heaving and pitching of the oscillating bow fin motion, finding the range of phase angles which enhance the speed of the ship model in wave. These results are compared with the mean speed in wave without flapping the oscillating bow fin. The experimental results show that it’s effective to enhance the speed of the ship model and to save energy in wave propulsion by applying an oscillating bow fin as long as the phase angle between heaving and pitching motion of the fin is in the appropriate range.