Investigation of the Resonant Effect in Carangiform Locomotion

In view of the soft bodies and complex muscle activities, many fishes may utilize resonance to save the energy required for undulatory locomotion. To confirm this hypothesis, we develop a new model of fish swimming to investigate the swimming performance. The model, combing decoupled natural orthogonal complement matrices with the large-Amplitude elongated-body theory, can be suitable to solve fish propulsion problems. Both simulations and experiments show that there does exist resonance phenomenon in carangiform locomotion when the driving torque is small. The impact factors for the resonant effect are also explored. The drag coefficient impact the resonant effect obviously while lift coefficient has almost no impact on the resonant effect. These properties can provide beneficial guides to design novel efficient biomimetic robotic fishes.