Bioinspired fin propulsion offers unique advantages over rotary blade propulsors for small and medium-size watercraft. Fins are not affected by cavitation or entanglement and are quieter than propellers. The thrust and efficiency output of such bioinspired propulsors result from the combination of actuation kinematics structural and geometric properties making optimization somewhat more complicated. This work experimentally investigates the effect of leading edge – trailing edge phasing during the oscillatory motion of a flexible fin resembling those of a manta ray. This thesis also evaluates the effect of placing tubercles on the fin's leading edge, which is a natural feature of humpback whale flippers and could increase propulsion efficiency. Here it has been found that the phasing co...[ Read more ]

Bioinspired fin propulsion offers unique advantages over rotary blade propulsors for small and medium-size watercraft. Fins are not affected by cavitation or entanglement and are quieter than propellers. The thrust and efficiency output of such bioinspired propulsors result from the combination of actuation kinematics structural and geometric properties making optimization somewhat more complicated. This work experimentally investigates the effect of leading edge – trailing edge phasing during the oscillatory motion of a flexible fin resembling those of a manta ray. This thesis also evaluates the effect of placing tubercles on the fin's leading edge, which is a natural feature of humpback whale flippers and could increase propulsion efficiency. Here it has been found that the phasing could help momentum generation by forming a chordwise traveling wave surface effect by the flexible fin. At the same time, tubercles could affect the leading-edge vortex formation.