Analysis of The Validity of Momentum and Energy Transferred to The Surrounding Water by Long-based Flexible Fins

Swimming is a common and effective movement in fishes. Locomotion is the result of momentum transfer from the fish musculature to the surrounding water. The present paper discusses how momentum and energy are conveyed to a perfect (inviscid and incompressible) fluid by a deformable body that moves in a fluid. The validity of momentum and energy transferred to the surrounding water by long flexible fins is analyzed. It is shown that long flexible fins undulating provides an effective means of momentum transfer, by allowing large amounts of water to be moved by small body masses.