| Abstract | The liquid sloshing mechanism is used as an energy absorber to suppress the vibration of
slender structures, normally caused by the effect of wind. The sloshing behavior may be
considered as linear for small excitation amplitude but for moderate to large excitation amplitude,
it becomes highly nonlinear. The nonlinearity includes amplitude dependent natural frequency,
free surface with moving nodal point, superharmonic resonance, wave breaking etc. Therefore,
the study focus on nonlinear behavior of liquid sloshing, because of its significance in predicting
the actual damper behavior.
A nonlinear analytical model was developed for liquid sloshing in rectangular tank based on
the Hydrodynamic theory, which comprises of Laplace continuity equation, nonlinear kinematic
and dynamic free surface conditions. The governing equations for liquid sloshing becomes very
complicated due to the consideration of nonlinear terms. Therefore, the perturbation technique
was applied upto the second order to foimulate the nonlinear model. The developed model can
predict the free surface shape, sloshing force, superha1monic resonance, wave breaking etc. The
effect of pure water damping did not incorporate into the model. As a result, the model predicts
unbounded sloshing amplitude and sloshing force at resonance. The developed model was also
simplified into linearized foim in order to compare with existing linear theories. The model was
compared with Tospol's (1993) linear model and Bauer's (1967) linear and nonlinear model. A
very good agreement was observed with the existing models.
An experimental investigation was conducted using a tank having dimensions 40 cm long,
20 cm wide, 45 cm height. The water depth in the tank were varied from 8 cm to 32 cm. Various
experimentally observed results were compared with the theoretical results. A good agreement
was observed with the experimental and theoretical results. However, some of the experimental
results can not be explained by the proposed theory, such as bounded response for sloshing
amplitude, and sloshing force at resonance; and amplitude dependent natural frequency. |