Study on the influence of external wind field on the terminal trajectory of projectile-parachute system

Abstract

Parachutes are used for aerial projectile deceleration and trajectory control in the military field. Although the existing multi-degree-of-freedom and multi-body dynamics model has a small amount of calculation, the external wind field in this model is simplified, and the influence laws of which on the terminal trajectory are not clear. Therefore, a projectile-parachute system is regarded as the research object in this work. A Fluid-Structure Interaction (FSI) model was used to analyse this system’s terminal trajectory. The cases with different wind velocity, wind directions, and initial trajectory angles were calculated. As a result, the external wind field has a great influence on the terminal trajectory of this projectile-parachute system. The difference in impact points in cases is positively correlated with the external wind velocity. At the same wind velocity, the trajectory in the upwind condition is easier to change than that in the downwind condition, and the difference in impact points is negatively correlated with the initial trajectory angle. While the external wind field has little influence on the projectile-parachute system’s deceleration, the swing angle, and the trajectory angle of the canopy. This system’s deceleration effect in the initial dropping process is more obvious under the upwind condition, and the deceleration effect will tend to be the same with the trajectory angle close to 90 degrees. Therefore, the influence of the external wind field on the terminal trajectory can be effectively reduced by increasing the initial trajectory angle, and the changes in canopy swing angle and trajectory angle will tend to be more stable in this situation