Rapid Simulation of 3D Liquid Sloshing in the Lunar Soft-Landing Spacecraft

Abstract

Sloshing of liquid fuel has significant implications in the accurate control of the spacecraft. Rapid simulation of the force and moment exerted by liquid against the spacecraft is rather important for the dynamics and control of the spacecraft. Fast numerical simulation models, especially those capable of dealing with violent liquid sloshing in the lunar soft-landing spacecraft with fluid merging and splitting, are required for real-time control algorithms. For this purpose, a modified smoothed particle hydrodynamics method, namely, noninertial smoothed particle hydrodynamics (NI-SPH), is proposed. In this method, noninertial coordinate system is used to derive transient external excitations to liquid. Meanwhile, the linear and angular momentum theorems of the particle system are adopted to calculate the force and moment exerted by liquid against the spacecraft, which avoids the accuracy loss of the integration of pressures. Furthermore, parallelization based on OpenMP is used to speed up the simulation. To show the accuracy and efficiency, results from the NI-SPH method are compared with those obtained by traditional computational fluid dynamics software, for several 3D liquid sloshing cases.