Hydrodynamic analysis of propulsion process of zebrafish

This study analyzes the kinematic characteristics and flow field information of zebrafish in straight and steering acceleration states using time-resolved particle image velocimetry to explore how vortices are generated and controlled to achieve the desired motion. The important role of the high- and low-pressure zones in the wake of zebrafish wavy propulsion is also presented by quantifying the pressure field around the zebrafish. With their precise body and motion control, fish have a movement advantage that cannot be achieved by artificial machinery. Exploring the evolutionary process of the fish structure and surrounding flow field during zebrafish autonomous propulsion is helpful for understanding the active control means and propulsion mechanism of fish. Zebrafish were constrained in a transparent water tank, and laser and image acquisitions systems were used to capture their spontaneous movement behavior. The results show that the pull provided by the low-pressure area and the thrust provided by the high-pressure area together provide the forward power of the zebrafish. The findings from this analysis of the bending control and propulsion mechanism of the zebrafish body can facilitate the optimal design of underwater vehicle propulsion methods, such as the propulsion efficiency and maneuverability of a bionic propeller.