Multi-body separation of flight vehicles is challenged by potential collisions that critically affect dynamic stability. This study develops a numerical method for simulating coupled aerodynamics, kinematics, and collision dynamics. Building upon a conventional computational fluid dynamics/rigid body dynamics (CFD/RBD) framework, the proposed approach integrates a collision dynamics model based on impulse–momentum theory and Coulomb’s friction law, together with a parallelized collision detection algorithm employing edge-face bounding boxes. A loosely coupled staggered solution scheme is established to effectively overcome the limitation of overset mesh in handling colliding bodies. The method is validated through store separation and rigid sphere collision, confirming its capability in resolving aerodynamic/kinematic coupling and normal/tangential collision responses. Application to a cluster munition separation case reveals shell behaviors at distinct initial velocities and identifies a critical safety boundary when the initial shell separation velocity reaches 3.25 times the projectile velocity, defining kinematic and aerodynamic threshold criteria for collision-free separation. Quantitative error analysis shows that the velocity and angular velocity errors from the aerodynamic approximation remain below 2.5% of the collision-induced increments, confirming the method’s engineering accuracy. Flowfield analysis shows that lower velocities result in severe shock interference and collision, whereas higher velocities enable rapid clearance, aerodynamic recovery, and clean separation.
Qin et al. (Sat,) studied this question.