sloshing simulation in abaqus

Hi i am modelling rigid cylindrical tank partially filled in ABAQUS with water provided an harmonic excitation A sin(wt) to validate result but i seems acceleration is high and fluid is sloshing out of cylinder which is not the case the experimental results. i am i am doing mistake in interaction part or boundary condition , i have give acc. at bottom edge of tank and other BC are for restricting water to move out of eulerian domain, and provided general contact with default setting.
other query was how to find natural frequency and mode shapes.
i am totally stuck here. you suggestion are invited.