Problem of dynamics of a reservoir of cylindrical shape, partially filled with liquid, on pendulum suspension with movable suspension point is under investigation. The problem is considered in nonlinear statement with the purpose of clarification of the effect of pendulum suspension on both frequency characteristics and the system behavior in the near-resonance zone. Analytical and numerical study shows that normal frequencies of oscillations have considerable changes for both quasi-rigid pendulum mode of motion and especially for frequency of liquid sloshing modes. Numerical examples show that resonant properties of the system for below resonance, above resonance and near resonance modes are considerably different and the effect of amplitude modulation manifests strongly for all cases.

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