Study on the initial external ballistics of airborne subsonic submunitions

DOI:	10.11809/bqzbgcxb2023.03.004
Keywords:	airborne dispenser; submunition; Fluent; aerodynamics; rigidtrajectory
Abstract:	In order to obtain the influence law of different ballistic shapes on aerodynamic characteristics of airborne dispenser submunitions and initial external ballistics under subsonic flows, this paper uses the computational fluid dynamics software FLUENT to simulate and analyze the aerodynamic performance of the submunitions with different body shapes under subsonic flows. A rigidsix degree of freedom external ballistics model of airborne dispenser submunitions is established, and their initial external ballistic performance is solved based on Runge Kutta methods. The result shows that the laminar/turbulent flows of air streaming under the influence of the projectile shape is the key factor which affects the aerodynamic force born by the projectile. The head protrusion of the projectile barely has any influence on its aerodynamic characteristics. Under a flow speed of 0.72 Ma, the coefficient of drag and the static moment derivative coefficient of a round head submunition are 0.349 and 0.86 respectively, which are 31.4% and 46.7% of those of a flat head one.With the same total wing span area, the aerodynamic lift force of the projectile decreases along with an increase of wing quantity. The static moment coefficient of the eight wing projectile is 58% of that of the six wing one. The angle of attack converges faster for the concaved head projectile and the six wing projectile in the initial external ballistics flight of the both projectiles, and the rate of attack convergence slows down when the radial rotation of inertia increases. The research results have a certain reference for the design of airborne dispenser submunitions.
Published:	2023-03-28
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