Numerical Study of the Thrust and Energy Consumption and Propulsive Efficiency of a Three Joint Bending Propulsion Mechanism

摘要

In our previous paper, we proposed a numerical method based on the discrete vortex method for a bending propulsion mechanism of fish or cetaceans in water, and we demonstrated its validity by comparing the results with an experiment using a three joint bending propulsion mechanism. In this paper, using this numerical method, we will analyze the characteristics of the thrust, energy consumption, and propulsive efficiency of a three joint bending propulsion mechanism in terms of normalized propulsive speed and the phase differences of the adjacent joints. We found that the thrust decreases due to the increase in the lift force as the normalized propulsive speed increases when all the joints move in phase. We also found that the propulsive efficiency has a maximum value when the normalized propulsive speed is 0.8 and when all the phase differences between the joints are 100 degrees.