Aerodynamic Characteristics Calculation And External Ballistic Simulation Of Bullet

The accurate calculation of aerodynamic characteristics and ballistic characteristics is an important step in the design of bullets and the optimization of bullet shape.In order to realize the rapid and accurate calculation of these two steps,the engineering algorithm and CFD simulation calculation method of the aerodynamic characteristics of the bullet were studied.Based on the construction of the aerodynamic characteristics of the bullet based on the "standard projectile" for quickly and accurately calculating the aerodynamic characteristics of the bullet.The aerodynamic theory of bullet is mainly based on the corresponding theory of fluid mechanics.In order to study the variation law of aerodynamic characteristics of guns,the shock theory,the theory of expansion wave and the corresponding theory of fluid separation in the flow field of guns were studied.In order to verify the "standard projectile" model,CFD was used.The aerodynamic parameters were provided,and the basic flow of CFD simulation and the corresponding theoretical methods were introduced.The engineering algorithm was based on the component combination method,which divides the bullet into the head,the tail and the cylinder to calculate the axial direction under different Mach number and angle of attack.The force coefficient,the normal force coefficient and the pressure core coefficient were obtained by combining the various aerodynamic coefficients by linearization theory to obtain the aerodynamic parameters of the bullet.Based on the "standard projectile",the aerodynamic characteristics calculation model of the bullet was based on the engineering algorithm,and the "standard projectile" idea was introduced.The bullet shape was compared with the standard bullet,and the corresponding correction amount and correction coefficient were obtained.The pneumatic in the "standard projectile" The corresponding correction amount and correction coefficient were added to the parameters to calculate the corresponding aerodynamic parameters of the bullet;after completing the calculation model of the aerodynamic characteristics of the bullet based on the "standard projectile",the calculation model was programmed by matlab,and the calculation was based on the 12.7mm bullet.The calculation results were compared with experimental results and computational fluid dynamics(CFD)simulation results to verify the accuracy of the model;Based on this calculation model,the influence of the length of the bullet shell,the length of the tail of the projectile and the tail cone angle of the projectile on the aerodynamic characteristics of the projectile was studied,and the corresponding analysis is carried out.The cause of the formation of the law.The 4D and 5D ballistic calculation models were established.The Ballge equation was solved by the Runge-Kutta method.The ballistic calculation program and the aerodynamic calculation program are written by Matlab,and the combination of the two and Monte Carlo method was applied to the projection and distribution of a 12.7mm gatling weapon..