Experimental observation on violent sloshing flows inside rectangular tank with flexible baffles

• A series of experiments was conducted on sloshing flows inside a rectangular tank with internal baffles. • Violent flows and baffle motions were observed in the cases of hyper-elastic and rigid baffles. • The local flows and dynamic pressure were measured and the results were compared for the different baffles. • Flow becomes very complicated at motion frequencies higher than linear natural sloshing frequency. • Flow becomes also complicated when the height of baffle is closer to free surface. In this study, a series of sloshing model tests were conducted to observe the effects of an internal baffle in a rectangular tank and to secure basic data for future numerical calculations or applications to similar phenomena. The sloshing flows and flexible motions of two different baffles with hyper-elastic properties were observed and the results were compared with those of a non-flexible baffle. Experiments were conducted for different filling conditions, motion amplitudes, and excitation frequencies, with a particular focus on violent flow cases. The local flows around the baffles were captured using a high-speed camera, and the sloshing-induced impact pressures on the tank walls were measured. The present experiment showed strong interactions between flexible baffle motion and sloshing flows, particularly at motion frequencies higher than the natural sloshing frequency. The physical phenomena became more complicated when the free surface was closer to the baffle height. The data obtained in this study can be used as benchmark tests for numerical computation of strong-fluid interactions.