Aerial Movement Of Chaff Cloud And Electromagnetic Scattering's Modeling And Simulation

The chaff is a kind of passive interference that has a long history of use and has a great influence on improving the combat performance of the radar.The effect of chaff jamming is closely related to the diffusion characteristics of the chaff,the atmospheric conditions,the flow of air in the atmosphere,and the influence of the aircraft wake.Therefore,it is of great significance to study the air motion characteristics and electromagnetic scattering characteristics of the chaff.This thesis firstly introduces the research significance of chaff cloud and aircraft turbulence and the research status at home and abroad.It also describes the principle of interference of center of mass of chaff,and vividly illustrates the interference process.The physical properties of different types of chaffs,such as the speed of descent,the area of interception,the rigidity,and the blanking time,are described,which provide a reference for the use of chaff.The maximum electromagnetic scattering area of different types of foils was simulated and compared,and the use characteristics of the foil strips were analyzed and analyzed in conjunction with the simulation results,which provided practical significance for the analysis of chaff disturbances.Secondly,the dynamic characteristics of the diffusion of chaffs in the atmosphere are analyzed,and the meteorology of chaff strips is introduced.For a single foil strip,the force analysis was carried out,and the relevant influencing factors affecting the movement of the foil in the atmosphere were studied in detail.The specific influence of different factors on the diffusion of the foil stripes was discussed,and the corresponding empirical data was given.Afterwards,the trailing characteristics of the carrier's airborne motion affecting the movement of the chaff cloud are introduced,which is of great significance for the study of the motion characteristics of the chaff in cloud.Based on the existing theory of the physical model of chaff cloud and the analysis of the stress condition of the chaff,a full consideration of various influencing factors,combined with relevant empirical data,established a sphere diffusion model of the chaff cloud under specific conditions and made Corresponding simulation analysis,the simulation results are consistent with the measured physical model.Finally,the numerical simulation methods of aircraft vortex trails and simulated turbulence were studied.The formation areas,stable areas,unstable areas and fault areas of aircraft vortex trails were studied.The idea of airborne chaffs in air was expanded.Numerical simulation methods for simulating turbulent flow include DNS,LES,and RANS methods.The advantages and disadvantages of each method are briefly introduced.This paper focuses on the discrete vortex method,which mainly includes the theoretical basis of the discrete vortex method,such as point vortex,vortex section and closed vortex frame,and introduces the physical theory and disturbance speed of each part in detail.Secondly,in the case of large Reynolds number,a discrete vortex method was used to simulate the free-flow turbulence simulation method in separated flow and jet.Combined with the theoretical knowledge of diffusion and force analysis of chaff strips in the atmosphere,a discrete vortex was proposed.Method of chaff cloud air motion algorithm.