Effect of elastic deformation on flight dynamics of projectiles with large slenderness ratio

The elastic deformation of the newly projectiles with large slenderness ratio cannot be ignored with the increasing of flight speed and high maneuverability. Reynolds-averaged Navier-Stokes Equations are solved through CFD technique in this paper. Based on the frame of unstructured mesh, techniques of rigid-motion mesh and inverse-distance-weighted morphing mesh are adopted to treat the rigid motion of six degree of freedom(SDOF) caused by flight dynamics and flexible structure deformation caused by aeroelasticity respectively. Moreover, the six-degree freedom dynamic equations are solved with static aeroelastic equations with the mode-summation method. Numerical results of free flight case and static aeroelasticity case calculated using the in-house code both agree well with the experimental data respectively, which shows the validation of the numerical method. An air-to-air projectile model of X-X configuration is constructed to research the effect of elastic deformation on the trajectory of the projectiles with large slenderness ratio. Comparison results of flexible and rigid models show that the longitudinal and course trajectory of centroid is affected by the elastic deformation, and the oscillatory cycle of the orientation angle increases. Furthermore, the trajectories of rigid models with various centroid locations are computed, illustrating that the elastic deformation could move the aerodynamic center forward and weaken the margin of the stability.