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This paper performs a theoretical and experimental study of the effect of increasing the velocity of projectiles during the high-speed extrusion of the polyethylene piston through a tapered section (also called a “hydrodynamic” effect). Mathematical modeling is performed using two methods. The first method is a quasi-one-dimensional description of the polyethylene piston deformation on a moving computational grid. The second method is axisymmetric modeling using the ANSYS AUTODYN package. In the experimental studies, the polyethylene piston was preaccelerated using a propellant charge, after which the escape velocity of the projectile was measured. The escape velocity of the projectile after the tapered section increased up to 50% compared to the input velocity. The experimental results are consistent with the theoretical calculations.

We present a simple computer simulation model for the interaction of automatic guns with unarmed drones. Each drone is represented as a rigid body that consists of several simple bodies such as parallelepipeds, ellipsoids, etc. The simplified spatial trajectory of the drone is constructed using third-order Bezier curves. A relatively large group of unconnected drones may be simulated in a computationally fast way using this method. Automatic guns are agents that are shooting at drones with a single of burst fire relative to the ideal aiming point. We performed a simulation of the flight of several drones against several automatic guns for different conditions. As a result of this simulation, the spatial distribution of the drone hit probabilities, the special distribution of the fraction of defeated drones depending on the number of guns, and the influence of urban obstacles on the fraction of drones defeated are presented.