Wave breaking and swirls in a circular cylindrical container during lateral sloshing

Regimes of wave motion in a partially filled circular cylindrical container with water at a large fluid depth (depth-to-radius ratio, d/R ≃ 1.2) are investigated experimentally when the container is excited laterally around the natural frequency of the lowest harmonic asymmetric mode (1,1). The sloshing motion near the resonance exhibits different types of wave motion, viz., planar wave, chaotic waves, swirls. Wave motion is found to depend on forcing frequency, fluid depth, forcing amplitude, and viscous damping. In the planar wave breaking regime, steep waves are identified, which shows amplitude modulations without breaking. When the forcing amplitude is high, the wave motion becomes nonplanar and eventually chaotic. When waves are excited above the natural frequency, bifurcation to swirl motion is observed. For a fixed forcing frequency, swirl height is seen to increase linearly with amplitude of forcing till the wave breaks based on the steepness limited criteria (swirl height/wave length ≥ 0.16). A sequence of events at high amplitude forcing in the breaking regime are presented here that describes the quasi-periodic transient response of the wave state: the growth of planar wave, breaking of planar wave, swirl, damped wave motion. A different type of coexistence, as observed in the single-mode Faraday waves, is found to be present where harmonic asymmetric mode (1,1) coexists with superharmonic mode (2,1).