Hysteresis in Shallow Water Sloshing

Hysteresis in sloshing of shallow water in horizontally excited tanks is explored experimentally. In particular the wave response to relatively large shaking amplitude near the resonant frequency is investigated for two tank configurations: a tank with horizontal bottom and vertical walls, and a tank with horizontal bottom and sloping beaches. The hysteresis behavior is clearly observed within a narrow frequency range around the shifted resonant frequency. The wave response is either in the form of smooth nonbroken waves or in the form of violent breaking waves for exactly the same set of parameters depending only on how the target oscillation frequency is tuned: i.e., whether the forcing frequency of the prior state is higher or lower than the target frequency. The consequence is that it is not possible to define a unique value for the jump frequency as it depends on the direction of the frequency tuning.