Supersonic accelerators use sabots to suppress bore balloting. However, sabot separation induces flight deviation in projectiles owing to their interactions with fluids and shock waves. A seamless calculation of the acceleration phase in the tube and the full separation process using 3-D computational fluid dynamics coupled with rigid body dynamics is presented in this study to investigate the shock-wave interactions around a railgun-launched projectile. The railgun acceleration induced a normal shock wave propagating ahead of the projectile; when the projectile reached the tube end, a substantial expansion at the muzzle generated two shock waves, namely, a spherical precursor shock wave and a Mach disk, outside the tube. Aerodynamic forces on the projectile/sabot decreased to almost zero just after the tube exit, with the ambient fluid around the tube being faster than the projectile by the substantial expansion. After exiting, the projectile penetrated the precursor shock wave at $t=0.15\mathrm{ms}$; this increased the aerodynamic forces acting on the projectile, initiated sabot separation, and generated multiple shock-wave interactions, which induce unsteady aerodynamic loads on the projectile.

超音速加速器使用弹壳来抑制钻孔。然而，由于弹丸与流体和冲击波的相互作用，弹壳分离会导致弹丸的飞行偏差。在这项研究中，使用 3-D 计算流体动力学和刚体动力学对管中的加速阶段和完全分离过程进行了无缝计算，以研究轨道炮发射弹丸周围的冲击波相互作用。轨道炮的加速度引起了一个正常的冲击波在弹丸前方传播；当弹丸到达管端时，枪口处的大幅度膨胀在管外产生了两个激波，即球形前驱激波和马赫盘。弹射体/弹壳上的空气动力在管退出后立即减少到几乎为零，管周围的环境流体由于大幅膨胀而比射弹更快。出射后，弹体在以下位置穿透前驱冲击波$吨=0.15\mathrm{小姐}$; 这增加了作用在弹丸上的空气动力，启动了弹壳分离，并产生了多重冲击波相互作用，从而在弹丸上引起不稳定的空气动力学载荷。