A Research On Flight Mechanism Of Dandelion Like Aircraft

Dandelion seeds have attracted wide attention because of their long-distance flight ability and slow descent characteristics in the process of transmission.Under the trend of small size,light weight,better concealment and maneuverability,dandelion seeds'excellent flight performance and its pappus structure can meet the needs of future aircraft development.The research on the flight mechanism of dandelion seed and its bionic aircraft may provide a new design idea for the development of long endurance and low energy consumption micro bionic aircraft.This paper aims at the research on the flight mechanism of dandelion like aircraft,analyzes the resistance characteristics and stability characteristics of dandelion seeds in the flight process,establishes an effective model of dandelion like aircraft according to the biological morphological parameters of dandelion seeds,and explores the main factors affecting the resistance characteristics of dandelion like aircraft and its influencing mechanism.The main research content is divided into four parts.The first part mainly studies the biological characteristics of dandelion seeds in nature.Based on the resistance theory of microbial flagella,the force situation of dandelion seeds in flight is analyzed,and the corresponding resistance coefficient calculation formula is given,and the main factors affecting the resistance coefficient of dandelion like aircraft are analyzed from the theoretical point of view;the second part mainly studies the effective model construction of dandelion like aircraft,referring to the bioassay results and the theoretical model,the geometric model of dandelion like aircraft is established.The permeability expression of the model is proposed,and the existence of SVR is analyzed.At the same time,the resistance coefficient of the model is calculated by simulation,and compared with the resistance coefficient of natural dandelion seeds to verify the effectiveness of the dandelion like aircraft constructed in this paper;the third part mainly studies the influence of pappus shape,pappus number and porosity on the drag coefficient of dandelion like aircraft,and analyzes the influence of pappus shape,pappus number and porosity on dandelion like aircraft from the perspective of simulation In the fourth part,the influence of the incoming flow on the drag coefficient of the dandelion like aircraft is studied.Through a series of theoretical analysis and simulation experiments,this paper explores the basic problems of the stability mechanism,lift and drag characteristics of the dandelion like aircraft,and obtains the general conclusions about the influence mechanism of the vortex stability and drag characteristics of the dandelion like aircraft.Permeability is an important condition for dandelion seeds to produce SVR.When the porosity of dandelion like aircraft with cylindrical pappi is in the range of natural dandelion seed porosity,its Da value is between 10^-5 and 10^-4,which meets the necessary conditions for producing stable SVR.At the same time,the resistance coefficient of dandelion seeds is similar to that of natural dandelion seeds.Without weakening the interaction between pappi,the resistance coefficient of dandelion seeds can be increased by reducing the number of pappi.When the flow direction is between55 and 60 degrees,the dandelion like aircraft can obtain the maximum resistance coefficient in the vertical direction to slow down the descent speed and provide time for long-distance flight.The dandelion like aircraft model proposed in this paper can achieve the goal of morphological bionics and functional bionics.It provides an important theoretical support for the further design of dandelion like aircraft.