不同攻角条件下偏转头弹箭流场与气动特性

基于DES(detached eddy simulation,分离涡模拟)方法及AUSM(advection upstream splitting method,对流迎风分裂方法)格式,对不同偏角的偏转头弹箭在非零攻角下的超声速流场和气动特性进行了数值模拟.结果表明:在非零攻角情况下,与常规弹箭流场相比,偏转头弹箭头部迎风面激波更强;而当有效入射角相等时,即使弹箭的攻角不一样,其头部流场结构仍相同,且尾翼流场基本不受头部偏角影响.另外,由气动力系数变化曲线可知,偏转头弹箭具有良好的纵向静稳定性,且升力系数随攻角的增长率大于阻力系数,即升阻比大于常规弹箭,因此适当增大攻角可以提高偏转头弹箭的气动特性.

Flow field and aerodynamic characteristic of deflectable nose projectile at different angles of attack

Based on DES (detached eddy simulation) method and AUSM (advection upstream splitting method) scheme, the supersonic flow field and aerodynamic characteristic of deflectable nose projectile were simulated numerically at non-zero angle of attack and different deflectable angles. The results show that, at non-zero angle of attack, the shock wave on the windward of the projectile head with deflectable nose was much stronger than that of the normal one. When the effective angles of incidence of both projectiles were equal, the structures of flow field of head were all the same, and the flow field of tail fins were not affected by the deflectable angles even different angles of attack of projectiles. From the time history of aerodynamic force coefficients versus angle of attacks, it's found that the projectile with deflectable nose has good longitudinal static stability. Besides, the raising gradient of lift coefficient is much larger than that of drag coefficient, showing the lift-to-drag ratio is higher than normal projectile. Therefore, increasing the angle of attack properly can improve the aerodynamic characteristic of deflectable nose projectiles.