CFD Analysis of the Lateral Sloshing Phenomenon inside an Aerospace LH2 Cryogenic Tank

In this work, we propose to perform unsteady 3D numerical simulations by means of the VOF methodology to understand the behavior of the lateral sloshing inside an aerospace LH2 cryogenic tank. The first geometry considered is a simple laboratory-scale cylindrical tank model, designed to investigate the sloshing phenomenon with the presence of a single baffle ring. The case is used to assess the capability of the adopted method to predict the correct sloshing damping. The second geometry under study is instead inspired to a typical common bulkhead cryogenic tank used in space launchers. Simulations investigate sloshing inside the tank under normal gravity conditions. The unsteady lateral force on the tank wall, as well as the center of gravity position, obtained from the simulations are used to obtain and validate a reduced-order model (ROM) that takes into account the non-linear nature of the damping. Lateral loads are then analyzed through Fourier spectral analysis and through wavelet analysis, decomposing the time series into the time-frequency domain, to determine the time evolution of the energy of the excited mode.