Study on the dynamical characteristics and experimental validation for liquid sloshing in a common bulkhead tank

In this paper, the dynamic characteristics of the liquid slosh in the common bulkhead tanks are investigated by the numerical method, experimental method, and equivalent mechanical model. Research results show that the first slosh frequency increases with the increase of liquid depth ratio. Nevertheless, the second slosh frequency decreases with the increase of the liquid depth ratio. In addition, two examples are presented to validate the improved moving pulsating ball model and the results are well in agreement with the numerical and experimental results. Furthermore, the complicated multi-modal or higher order modal characters of the nonlinear liquid sloshing in common bulkhead (CBH) tank are investigated by computational fluid dynamics (CFD), and it is shown that the higher order mode patterns can still appear obviously under strong excitation. Finally, the rotary sloshing and symmetrical rotary sloshing phenomenon in the CBH tank is revealed experimentally and it was found that rotary sloshing would become unstable and evolves into the symmetrical rotary sloshing due to value changes of excitation amplitude and excitation frequency. This symmetrical rotary sloshing cycle would start intermittently at a specific rhythm depended on the frequency of the excitation.