Dynamic Model of Rifle Bullets in Muzzle Flow

The development of high accuracy rifle has uncovered a need for understanding the movement of the bullet in muzzle flow. Recent researches have always been focused on computational fluid dynamics (CFD) and experimental research on the muzzle flow, which released many data, such as velocity and base pressure drop of projectile. Due to CFD tests are timeconsuming, a dynamic model for spatial motion of projectile is established. In this model an empirical relationship is utilized for the base pressure of projectile, and the model is assumed that the base pressure is along the axis of barrel which applied on the tail cone of the bullet; The spatial motion equations deduced from the mass center motion equations and Euler equations of motion are solved with Runge-Kutta method. A 7.62 caliber bullet is tested to verify the dynamic model. The result agrees with the CFD and experimental data, which shows that the model is applicable in predicting the translational motions, besides the angular motion of projectile is also presented, which can be the initial condition of exterior ballistics to analyses the firing accuracy.