Effect of Bending Deformation on the Lateral Force of Spinning Projectiles with Large Aspect Ratio

The bending deformation can affect the lateral force of spinning projectiles with large aspect ratios, thus interfering with their flight stability. Based on the established spin-deformation coupling motion model, the unsteady Reynolds averaged Navier-Stokes (URANS) equations are solved to simulate the flow over a large-aspect-ratio projectile undergoing spin and spin-deformation coupling motion by using the dual-time stepping method and dynamic mesh technique, obtaining the lateral force. Furtherly, the flow mechanism is analyzed for the changed lateral force induced by the bending deformation. The results indicate that the variation of transient lateral force for the head of a projectile is consistent with that of the deformation-induced additional sideslip angle; affected by the deformation-induced compression wave and expansion wave, the time-averaged lateral force for the middle of a projectile will be increased at small angles of attack, but changed little at large angles of attack; at small angles of attack, the change trend of transient lateral force for the tail of a projectile is similar to that of additional angle of attack caused by the deformation; at large angles of attack, the characteristic of phase lag is presented between the transient lateral force for the tail of a projectile and the additional sideslip angle.