A new secondary instability phenomenon of parametric sloshing.

This paper reports on a new secondary instability phenomenon of parametric sloshing. Faraday first experimentally discovered the (1/2 sub-harmonic) parametric sloshing phenomenon in 1831. The parametric instability starts from a small disturbance on the free fluid surface, and then the sloshing amplitude of fluid increases exponentially and finally reaches a steady-state limit cycle oscillation. This parametric instability is called the first (linear) instability. The parametric sloshing experiment of this study discovers that in the case of the parametric excitation unchanged, the free fluid surface that is in a limit cycle oscillation might undergo a secondary instability. Under this circumstance, the sloshing amplitude of free surface increases sharply. The consequence is catastrophic - the fluid is splashed out of the tank. During the secondary instability, the sloshing mode (or energy) is transferred from the third mode to the first mode. The secondary instability, which is different from the first instability, is a nonlinear unstable process. The mechanism of the secondary instability is needed a further study. [ABSTRACT FROM AUTHOR]