Unsteady Numerical Simulation on Motion Characteristics of Combination of Rocket and Separating-Capsules during Torpedo-Rocket Separation

To study the motion characteristics of the combination of rocket and separating-capsules, a multi-body dynamics model during torpedo-rocket separation is established based on Lagrange method and is embedded into the flow field solver. Unsteady numerical simulation on the torpedo-rocket separation is performed using the overset mesh method. The validity of the numerical method is proved through comparison with the experimental results of rocket sled. The motion characteristics of the combination of rocket and separating-capsules under different separating conditions are analyzed through simulation. It is shown that the attitude of the rocket has significant effect on the open synchronism of the upper and lower separating-capsules’ during separation. And the aerodynamic characteristics of the rocket significantly influence its attitude change, i.e. when the separation attack angle is 1.5° or 0°, the rocket pitches up under the action of aerodynamic force, resulting in asynchronism of the separating-capsules. When the separation attack angle is –1.5°, the attitude of the rocket remains stable and the open synchronization of the separating-capsules keeps well. Thus the aerodynamics of the rocket as well as the interaction between the rocket and the separating capsules should be fully taken into account in design of torpedo-rocket separation scheme, and the separating condition should also be considered to improve the safety of separation.