Modeling and simulation of the intermittent swimming gait with the muscle-contraction model of pre-strains

Abstract

The muscle-contraction model of pre-strains is employed to study the intermittent swimming gait of a 2D freely swimming fish. The fluid-structure interaction problem of fish swimming is solved with the finite elements method. Benefits of the intermittent swimming and the effects of the duty cycle and the tail swing number in a burst phase are emphasized. The results show that, compared to the steady swimming, a huge energy saving for swimming can be achieved by sacrificing a little speed during the intermittent swimming. Moreover, the fish swimming can be gradually transited from an intermittent mode to the continuous mode by increasing the duty cycle. With a smaller duty cycle, the fish can save more energy to obtain the same swimming velocity. A smaller tail swing number in a burst phase is more helpful to improve the energy utilization rate under the condition of Rduty = 0.5. In addition, the intermittent swimming will have more benefits at the lower and the higher average swimming speeds, and it is very important to have a proper proportion of the velocity bounds for the performance improvement of the intermittent swimming. These conclusions may have direct meanings for the development of biomimetic autonomous underwater vehicles.