Strap-On Boosters Separation Analysis Using Coupled Simulation of Constraint Dynamics and Time Dependent CFD

A numerical dynamic-aerodynamic interface for simulating the separation dynamics of constrained strap-on boosters jettisoned in the atmosphere is presented. Two commercial solvers: a 6DOF multi-body dynamic solver and a numerical time-dependent flow solver are integrated together with an interface code to constitute a package that presents real-time dynamic/aerodynamic coupled analysis. Dynamic unstructured mesh approach is employed using local remeshing methods in respect of bodies motion with a second-order upwind accurate 3D Euler solver. This interface can simulate multi body separation dynamics interaction with aerodynamic effects to complete separation mechanisms like springs, thrusters, joints and so on. The flow solver is validated by the Titan IV launch vehicle experimental data. The separation integration is used for a typical launch vehicle with two strap-on boosters using spring ejector mechanism and spherical constraint joints acting in the dense atmosphere. Hence, the aim of the presented interface is to facilitate the integration of complicated separation mechanisms with a full numerical CFD aerodynamic solver.