Study Of Aerodynamic Characteristics For The Subsonic And Transonic Wrap Around Fins Projectile

The wrap around fin has widely applicated in modern weapons because of its advantage of saving space and easy packaging. As to the projectile with wrap around fins without control, the special aerodynamic of the wrap around fin such as inducing the self-rolling and cross coupling seriously which are compared with the flat fin affect the flying stability in wide extent. The abroad keep ahead the China and the experiments take the lead the theory and calculation about the study in this aspect. So it is necessary to study the WAF deeply. In modern aircraft design, in order to meet the need of study, there is an urgent requirement for the accurate, efficient and easy-use aerodynamic data and computational analisis tools. However, the Euler codes are not satisfied all the demands for simulating the complex flow-field. More powerful tools for solving Navier-Stokes(N-S) equations are longed for viscous effect, more accurate and more detail information of flow-field.The study object is the projectile with wrap around fins. Arc Length method of grid generation is applied. The three dimensional N-S equations are solved by implicit LU-SGS and the Jameson central different scheme. It can be obtained Various of flow field at Mach numbers of 0.5,0.7,0.9,1.1,1.3 and 1.5 and angles of attack of 0,2,4,6 and 8. The coefficients of drag, lift, pitching moment, roll moment and so on are calculated by the integral of projectile surface force according to the flow field parameters.The result show that all the coefficients are changing when the Mach number and angle of attack are changing too, as well as the roll moment is changing its direction more than once. And try to find the range of the Mach numbers when the roll moment change its direction. The results accord with the aerodynamic theory and are rewarding for engineer to reference in wrap around fins design.