PREDICTION OF DRAG AERODYNAMIC COEFFICIENT OF THE 155MM PROJECTILE UNDER AXISYMMETRIC FLOW USING DIFFERENT APPROACHES

The determination of the total aerodynamic load which negatively influences the movement of artillery projectiles is inevitable and indispensable in order to be able to increase or control their ranges. The main part of this aerodynamic load that has the most influence on projectile movement is the drag force, which acts in the opposite direction to the velocity vector and therefore opposes its movement. From this, in this present work, the total drag coefficient of the 155mm M107 axisymmetric projectile under axisymmetric flow, at zero yaw, was predicted by semi-empirical and computational fluid dynamics (CFD) approaches in the three flow regimes, also the influence of its components on the total drag was analysed. The average deviation of the total drag coefficient in the three flow regimes, compared to the reference experimental results, is 5.7% for the semi-empirical results and 1.7% for the computational results. Analysis of the influence of the total drag components, such as pressure drag, friction drag and base drag, permitted to calculate their influence rates on the total drag as a function of Mach number and flow regime.