INFLUENCE OF THE POLAR AND EQUATORIAL DAMPING MOMENTS OF THE PROJECTILE ON ITS FLIGHT DISTANCE

Abstract

A relevant and important issue in the calculation of projectile flight trajectories is the definition and presentation of the equatorial and polar damping moments in the system of differential equations of spatial motion of projectiles. It is shown that the damping moments are determined by the shape and orientation of the projectile, the nature of the flow, the type of boundary layer and its interaction with shock waves, the speed, the height of the projectile and its nutation angle. To evaluate the influence of the aerodynamic coefficients of the equatorial and polar damping moments (their aerodynamic coefficients) on the flight range of the projectile, the method of differences is used, which consists in solving the system of differential equations of the spatial motion of the projectile so that changing the value of the aerodynamic coefficient results in a change in the flight range. Numerical modeling of the dependence of the flight range of the 155-mm HE Assegai M2000 projectile on the change in the aerodynamic coefficients of the equatorial and polar damping moments by 1% was carried out. It is shown that the aerodynamic coefficient of the polar damping moment creates the largest errors in the range at the maximum and minimum charges, namely, at the maximum charge the error reaches 0.012%D, at the minimum charge – 0.01%D, the effect on intermediate charges is manifested in a much smaller form, and not exceeds the value of 0.005%D. The largest error in the flight range of the projectile from the aerodynamic coefficient of the equatorial damping moment is observed at the maximum charge, the deviation reaches 0.07%D, the smallest error at the minimum charge is 0.0001%D. The obtained results make it possible to estimate the required accuracy of determining the aerodynamic coefficients of the equatorial and polar damping moments under different firing conditions of artillery systems.