Dynamics and initial experiments of bionic undulating fish fin

The undulating fin propulsion mode belongs to one of MPF (median and/or paired fin). This propulsion mode has great potential and bright prospect because of the remarkable advantages including capable of producing vector thrust, smaller disturbance to ambient flow field, as well as tending to transplant to underwater robots. In this paper, we will introduce a novel bionic propulsor which is called bionic undulating fish fin because its design is derived from the imitation to the structure and function of the undulating fin of aquatic animals. A simplified computational model to analyze the dynamics of the bionic propulsor is also proposed, and the dynamic model of the bionic propulsor including six components of forces and moments is derived theoretically. In addition, the basic relationships between the dynamics of the bionic propulsor with the undulating parameters and geometric parameters of fin surface as well as the velocity induced by its carrier are studied by simulation. At last, the validity of the analytic method presented by the paper and the rationality of its relevant conclusions are verified through conducting the thrust and moment testing to the bionic propulsor.