The Propulsive Mechanism Analysis Of Bionic Caudal Fin And The Research On Anti-drag

With the development of the society, marine resource has been appreciated for increasing depletion of land resources. The research on AUV has been attracted more and more attention as the AUV plays an important role in exploration and exploitation of marine resources. The development of the AUV is restricted by the traditional propeller, which is low efficiency and inflexible. The new type of propulsion, which is flexible, high efficiency and good concealment, has always become a hot pint in the research field of AUV and the development direction of AUV. After a long evolution, fish is endowed with extraordinary swimming ability which is high flexible and high efficiency with low energy consumption. Applying the swimming style to the study of propeller is considered important for design the new type of propulsion. The propelling mechanisms of caudal fin are explored, though the analysis of the flow field structure of sailfish caudal fin swing. And the caudal fin swing is imitated by bio-mechanism. The conclusions can be summarized as follows.The data of sailfish caudal fin is acquired through reverse engineering, which the research is based on. The unsteady flow field of pitching and heaving model is simulated numerically by means of the dynamic mesh technique of Fluent. The emergence of eddy following the fin and the theory of reverse karman vortex street are studied by flow field structure. Propulsion performance of caudal fin under different parameter like phase distinction, range of fin movement and strouhal Number are discussed. The propelling mechanisms of caudal fin are explored. The results show that the eddy following the fin turns into a shoot whose direction is backward. Then fish can be propelled with high efficiency. The caudal fin motion parameters can provide high propulsion for fish though coordination in an appropriate range.Though the hydrodynamic analysis of fish three-dimensional model and AUV model and comparing the numerical simulation analysis result, we can know that the fish body pressure distribution is more uniform and has a smaller resistance coefficient than the columnar body of AUV. The theoretical basis for optimization bionic AUV is provided, though the research conclusions.The generating theory of propulsive force from the caudal fin and caudal peduncle is researched, though the calculation of the simplified swing model. The type of caudal fin swing is imitated by bionic mechanism, though the research on the law of the swing of the caudal fin. The research on bionic mechanism provides theoretical basis for the study of efficient bionic propulsion system.In this paper, the propelling mechanisms of caudal fin are explored. The link mechanism is used to imitate the caudal fin swing, thus providing theoretical basis for the development of the new type of underwater propulsion equipment. The hydrodynamic analysis of the fish body and the traditional AUV body is expected to optimize the shell of the AUV. But fish attitude control and exercise flexibility has its own unique feature, need further more research.