Static and dynamic aerodynamic characterization and external ballistic analysis of fin-stabilized projectile using a coupled CFD/MATLAB framework

The speed and system reliability of magnetic reluctance-launched projectiles have been theoretically and experimentally verified. However, there is little research on the flight stability of such low-speed, non-spinning, and fin-stabilized projectiles, which affects the law enforcement application of this technology. This article establishes an analysis framework that couples steady-state computational fluid dynamics, unsteady forced oscillation transient computational fluid dynamics, and a rigid body trajectory model. Utilizing a linear least-squares fitting method based on the first-harmonic assumption, a static and dynamic aerodynamic database is constructed within the range of velocity of 20 to 60 m/s and an angle of attack range of −6° to +6°. The results show the following: (1) Under the studied operating conditions, the static stability margin of the projectile is 10%–22%, showing good static recovery ability, and the change in drag coefficient is relatively small. (2) The absolute value of the pitch combination dynamic derivative increases with the increase in speed, indicating that the increase in flight speed helps to enhance the dynamic damping capability. (3) The external ballistic simulation shows that under the selected typical initial angle of attack disturbance operating conditions, the projectile attitude can quickly converge in a short period of time, and the amplitude of angle of attack change during flight is small, exhibiting good attitude stability. The research can provide methodological support for the aerodynamic parameter analysis, external trajectory modeling, and flight stability evaluation of low-speed, non-spinning, and fin-stabilized, less-lethal projectiles and provides a reference for the design optimization and engineering application of related less-lethal projectiles.