Dynamic Analysis Of The Caudal Fin Propulsion System Of Single Joint Robotic Fish

With the further exploitation of marine resources,the research of underwater vehicles such as bionic robotic fish has got more and more attention.Nowadays,it has become a hot issue in the field of bionics.It is of academic value and practical engineering significance to explore the hydrodynamic mechanism of swimming in underwater fish.From the perspective of numerical simulation,the propulsion mechanism and efficiency of the caudal fin propulsion bionic robotic fish are analyzed and explored in this paper.In this paper,a single joint robotic fish is used as a prototype.First,the motion mechanism of single joint robotic fish and the selection of the caudal fin are analyzed with the theory of computational fluid dynamics.Then three dimensional modeling technique is used to construct a three-dimensional model of single joint robotic fish,and the correctness and accuracy of the model are checked.Secondly,the flow field of the caudal fin of robotic fish is simulated numerically through FLUENT numerical analysis software,the results show that: The average thrust of the fish increases with the rising of amplitude and frequency.As for the crescent caudal fin that is studied in this article,the variation of the average thrust with the oscillating frequency is greater than that of the swing amplitude.Through further analysis of the vortical contours and the pressure contours in the oscillating cycle of the caudal fin,the main factors for the production of the fish body thrust include: One is the force of the fluid acting on the caudal fin surface during the swing process in the proceeding direction of the fish,the other is the propulsive force of the tail flow field formed by the anti-karman vortex street.Then the influence of the geometric parameters of crescent caudal fin on the propelling force of the fish body is analyzed.The results show that the propulsion of the fish increases with the rising of the ratio of the aspect ratio and the sweep angle,and the aspect ratio is the main geometric parameter.Finally,by the analysis and comparison of the optimized crescent caudal fin and the original round tail,it is found that the propulsion efficiency of the crescent caudal fin is higher than that of the round tail,and the stationeriness is better.In this paper,the motion mechanism and hydrodynamic characteristics of a bionic robotic fish are analyzed by numerical simulation.It provides a theoretical basis for further design and development of bionic robot fish,and it provides a basis for the optimization design of bionic robot fish.