Supersonic Artillery Projectile Fin Deployment Simulation Methodology

Sophisticated artillery munitions with guiding capabilities might be fin stabilised and thus deployment time of the fins is then critical to achieve aerodynamic stability. As the travelling velocity of the projectile during fin deployment can be well in to the supersonic range, the wind loads are large enough to affect the deployment. When developing fin-stabilised projectiles numerical simulations can be a tool in the design process, in order to reduce both development time and cost. The dynamic event require a simulation method that can both capture the aerodynamic flow around the projectile and the deployment of the fins, and most important how they interact with each other.The goal of this master thesis is to evaluate whether a Fluid-Structure Interaction simulation using Arbitrary Lagrangian-Eulerian formulation in LS-DYNA is suitable to simulate fin deployment on a projectile travelling at supersonic speed.Several simulations were made in LS-DYNA starting with a risk assessment evaluating different important principles and modeling alternatives. The air flow around a projectile with static fins was then compared with a traditional CFD simulation. A fin deployment was finally simulated, both with and without wind loads.The main findings are firstly that LS-DYNA capture the important aspects of the air flow around a projectile, however further validation is needed regarding the accuracy of the pressure and velocity fields. Secondly, this type of simulation requires capable computers, both regarding calculation capacity and memory. Finally, the fin deployment times are in the range found from gun firing tests of fin-stabilised artillery munitions.Validerat; 20130620 (global_studentproject_submitter