Research On Lift Formation Mechanism Similar To Insects For Half-Rotating Wing Based On XFlow

Half-Rotating Wing(HRW)based on Half-Rotating Mechanism(HRM)imitates the flight of insects by continuously asymmetrically rotating wing,which makes HRW avoid the inertia force produced in reciprocating swing of wings and be more conducive to flight.Based on early research results of HRW,analysis on HRW lift formation mechanism was conducted by combining with the insect flight mechanism to provide support for aircraft lift formation mechanism and the way to improve its lift,which is of great significance for HRM to be applied in flight.With analysis and summary for the relevant research on the insect flight mechanism at home and abroad,HRW working principle and its basic movement were introduced.The flow field analysis models of HRW were established in XFlow.The geometric equations of motion were expressed according to its motion law,while the relevant parameters of the HRW flow field analysis models were set.Then the law of lift variation and the characteristics of flow field distribution were calculated when HRW was in the setting state.The basis of qualitative analysis was provided by determining the post-processing methods of lift and flow field for the lift formation mechanism of HRW flight.Based on the law of lift variation and the characteristics of flow field distribution of HRW,the lift formation mechanism of HRW was analyzed deeply.The influence of aspect ratio of the blade and the angular velocity of crank on the lift of HRW was obtained,and the key parameters which influenced lift were analyzed.By comparing the blade of HRW with the symmetrical rotating wing,it was indicated that the lift of HRW could be effectively generated due to its asymmetric rotational characteristic.The influence of distribution of vorticity,velocity and pressure around the blade on the lift force was clarified.Besides,the flow field characteristics of HRW were described,so that the lift formation and variation of HRW were explained.The effect similar to rotational circulation of HRW was analyzed,which initially revealed the lift formation mechanism of HRW and indicated the direction of raising its lift.The flow field analysis model of double blades of HRW was established.The law of lift variation for single-wing and double-wing of HRW was compared,and the law of lift variation of HRW in hovering flight with different airfoil interval was analyzed.The lift force in each interval value was fitted by Matlab,and the influence of the variation of airfoil interval on lift was obtained.The movement law of airflow in the flow field when the middle frame was added was given,while the influence of the distribution of velocity and pressurenear the blade on the lift of HRW was illustrated.Differences between the lift mechanism of HRW in hovering flight and Weis-Fogh effect were compared to further understand the lift mechanism of HRW in hovering flight.Research around lift formation mechanism of HRW prototype model in forward flight was conducted.The variation of lift at different angular velocities of crank and velocities of incoming flow in zero-angle of attack forward flight,as well as at different initial angles of attack in non-zero-angle attack forward flight was gotten.Furthermore,the movement law of the leading edge vortex around the blade,the spanwise airflow on the blade and the shed vortex from the blade were analyzed.Meanwhile,the similarities and differences between the lift mechanism of HRW in forward flight and effects of delayed stall and wake capture of insect flight were compared.