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Aerodynamical CFD Study of a Non-Lethal 12-Gauge Fin-Stabilized Projectile

Aerodynamical CFD Study of a Non-Lethal 12-Gauge Fin-Stabilized Projectile Nowadays, the trajectory model for a subsonic fin-stabilized projectile at a low angle of attack is typically a point-mass model (PMM), taking only gravity and a constant zero-yaw drag into account. This choice can be qualitatively justified for non-lethal projectiles given the short ranges. The disadvantage of this approach is the lack of prediction on the precision and the attitude of the projectile when hitting the target, because of a possible instability in flight. However, the use of non-lethal projectiles requires that the impact conditions are met, otherwise more serious injuries may occur. Therefore, the consideration of other forces and moments acting on the projectile in flight is mandatory to predict static and dynamic stabilities, already in the body shape design as well as in the controller design process in the field of non-lethal ammunitions. Starting from a geometry in caliber 12-gauge, static coefficients (drag, lift, and pitch) for different angles of attack using steady RANS simulations with a low-order turbulence model were found. Different trajectories were then analyzed using those coefficients and the difference between the PMM and a 3-DOF accounting for drag, lift, and pitch in function of the angle of attack is indeed negligible in height and in range as long as the launch conditions are completely undisturbed. The slightest destabilization makes the PMM completely inappropriate. Knowledge of the pitch damping coefficient then becomes a necessity to optimize stabilization following minor disturbances. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Human Factors and Mechanical Engineering for Defense and Safety Springer Journals

Aerodynamical CFD Study of a Non-Lethal 12-Gauge Fin-Stabilized Projectile

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Publisher
Springer Journals
Copyright
Copyright © 2019 by Springer Nature Singapore Pte Ltd.
Subject
Engineering; Mechanical Engineering; Structural Materials; Textile Engineering; Security Science and Technology
ISSN
2509-8004
eISSN
2367-2544
DOI
10.1007/s41314-019-0020-x
Publisher site
See Article on Publisher Site

Abstract

Nowadays, the trajectory model for a subsonic fin-stabilized projectile at a low angle of attack is typically a point-mass model (PMM), taking only gravity and a constant zero-yaw drag into account. This choice can be qualitatively justified for non-lethal projectiles given the short ranges. The disadvantage of this approach is the lack of prediction on the precision and the attitude of the projectile when hitting the target, because of a possible instability in flight. However, the use of non-lethal projectiles requires that the impact conditions are met, otherwise more serious injuries may occur. Therefore, the consideration of other forces and moments acting on the projectile in flight is mandatory to predict static and dynamic stabilities, already in the body shape design as well as in the controller design process in the field of non-lethal ammunitions. Starting from a geometry in caliber 12-gauge, static coefficients (drag, lift, and pitch) for different angles of attack using steady RANS simulations with a low-order turbulence model were found. Different trajectories were then analyzed using those coefficients and the difference between the PMM and a 3-DOF accounting for drag, lift, and pitch in function of the angle of attack is indeed negligible in height and in range as long as the launch conditions are completely undisturbed. The slightest destabilization makes the PMM completely inappropriate. Knowledge of the pitch damping coefficient then becomes a necessity to optimize stabilization following minor disturbances.

Journal

Human Factors and Mechanical Engineering for Defense and SafetySpringer Journals

Published: Aug 16, 2019

References