Modeling and Analysis of Aeroelasticity and Sloshing for Liquid Rocket

In this paper, based on the advantages of Newtonian mechanics method, mixed coordinate method, and analytical mechanics method, the dynamic model of rigid-aeroelasticity-sloshing coupling is established for longitudinal vibration and liquid fuel sloshing, as well as the coupling between elastic deformation and liquid sloshing and their influence on the liquid rocket motion are analyzed. Considering the coupling effect between aeroelasticity and liquid sloshing, a new flutter analysis model is proposed, and the corresponding flutter analysis is carried out. First, the simplified model of the body and the liquid of the tank are established. By using Newtonian mechanics and analytical mechanics method, the nonlinear structural dynamic model considering the 3-D vibration and liquid sloshing is obtained. Second, influence of rigid-aeroelasticity, rigid-sloshing, aeroelasticity-sloshing, and rigid-aeroelasticity-sloshing coupling is simulated and analyzed. Finally, a new simplified model for the analysis of the flutter of the body is built by taking into account the impact of the liquid fuel sloshing. The results demonstrate that the elastic deformation and liquid sloshing change the motion characteristics of the rocket, and there is a strong coupling between the aeroelasticity and sloshing. Meanwhile, liquid sloshing has different effects on the flutter in all directions.