AJCPP 2008 March 6-8, 2008, Gyeongju, Korea Supersonic and Subsonic Projectile Overtaking Problems in Muzzle Gun Applications Rajesh Gopalapillai, Suryakant Nagdewe and Heuy Dong Kim School of Mechanical Engineering, Andong National University, 388, Songchun-dong, Andong, Korea
[email protected] Toshiaki Setoguchi Department of Mechanical Engineering, Saga University, 1, Honjo, Saga 840-8502, Japan Keywords: Blast Wave, Projectile, Ballistic Range, Overtaking, Chimera Mesh Abstract A projectile when passes through a moving shock ambient gas that has early been perturbed by the blast wave, experiences drastic changes in the aerodynamic wave. Behind the contact surface, an unsteady jet is forces as it moves from a high-pressure region to a developed by the discharge of the compressed gas. low pressure region. These sudden changes in the This unsteady jet may often be accompanied by a forces are attributed to the wave structures produced shock wave, the strength of which is again dependent by the projectile-flow field interaction, and are on the projectile acceleration4. responsible for destabilizing the trajectory of the Following the unsteady jet, the projectile is projectile. These flow fields are usually encountered discharged, consequently leading to strong interaction in the vicinity of the launch tube exit of a ballistic between the projectile and the unsteady jet when the range facility, thrusters, retro-rocket firings, silo former passes through the preceding unsteady jet. The injections, missile firing ballistics, etc. In earlier effects of this interaction are usually reflected in the works, projectile was assumed in a steady flow field unsteady fluctuating forces that act on the projectile when the computations start and the blast wave itself5.