Analysis Of Hydrodynamic Performa Nce Of Swinging Wings With Adaptive An Gle Of Attack

The limited nature of human resources has attracted the attention of many researchers at home and abroad to the ocean with rich resources.My country’s development also needs the help of the ocean to further realize the strategy of maritime power.In order to improve the efficiency and maneuverability of underwater equipment for exploring the ocean,research shows that the bionic propulsion derived from the biological swimming method exhibits excellent performance.Among them,the bionic swing propulsion derived from fish swimming compares with It has outstanding advantages over traditional propeller propulsion methods.Therefore,it is of great practical significance to study the design method and working principle of the bionic swing-wing propeller.This paper mainly studies the design parameters,hydrodynamic performance and flow field characteristics of a single-degree-of-freedom adaptive angle-of-attack swinging wing.The specific research contents of this article are as follows:First of all,four dimensionless parameters of horizontal swing amplitude ratio,advance coefficient,frequency ratio and elastic coefficient ratio were extracted to characterize the movement of the swing wings for adaptive attack angle swing.In terms of numerical verification,NUMECA series FINE/Marine hydrodynamic analysis software was used to verify the grid independence.On this basis,the NACA0012 airfoil was used to perform the lift coefficient and propulsive efficiency of the swing wing.By comparison and verification,the results show that the FINE/Marine software used can accurately carry out numerical simulation research on the hydrodynamic performance of the swing wings.Secondly,the hydrodynamic performance of the self-adaptive angle-of-attack swinging wing under the independent action of four non-dimensional parameters is investigated.The results show that the horizontal swing ratio,advance coefficient,and elastic coefficient ratio of a single parameter have a greater impact on the swing performance of the swinging wing.The impact of the frequency ratio is small;in order to explore the influence of the airfoil shape on the hydrodynamic performance of the pendulum wing,this paper has done six propulsion efficiencies and average thrust coefficients for the six NACA series airfoils and six rounded flat series airfoils.The comparative analysis shows that the NACA00 series airfoil has superior propulsion performance;on the basis of the study of single motion parameters and airfoil shape,the variation rule of the swinging airfoil propulsion performance under the combined influence of multiple motion parameters is explored.The interaction trend between the three dimensionless parameters of advancement coefficient,frequency ratio and elastic coefficient ratio and the propulsion efficiency and average thrust coefficient is the contour curve.The three dimensionless parameters are manually found when the best swing performance is found.The optimal design interval of the parameter,and then randomly found two sets of parameter values within the given parameter design interval to verify the example.Finally,this paper further analyzes the hydrodynamic mechanism of the influence of four dimensionless parameters on the propulsion performance of the swing wing by extracting the flow field characteristics of the swing wing.Select the appropriate calculation point and post-process to obtain the local start-up vortex and the overall wake field of the swing wing.Observing the characteristics of the flow field,it is found that the horizontal swing amplitude ratio,the advance coefficient and the elastic coefficient ratio will affect the position and morphological characteristics of the start-up vortex;The horizontal swing amplitude ratio,the advance coefficient and the elastic coefficient ratio have a greater influence on the wake vortex shedding pattern in the wake field;the frequency ratio has less influence on the swing wing starting vortex and wake field.