Performance Optimization of a Fish-Like Propeller Based on Continuum Driving

The excellent swimming ability of fish provides a new solution for the design of underwater propellers. However, there is a lack of optimization schemes for the structure and performance of the continuum driving fish-like propeller. This letter introduces, for the first time, a continuum driving fish-like propeller capable of online adjustments to the ratio of its active part and passive part (RAP). Then, a hydrodynamic model of the designed platform is established based on the being gradually softened approach (BGSA) to analyze the active and passive bending of the caudal fin. Finally, the coupling effect of RAP and the passive part stiffness (PS) on the propulsion performance of the fish-like propeller is explored through experiments. Results indicate that matching RAP and PS with the kinematic characteristics is essential for optimal propulsion performance. With the increase of flapping frequency, RAP and PS need to be increased. This work provides valuable guidance and insights for the design and optimization of the continuum driving fish-like propellers.