Experiments on Vibrations of a Hollow Rotor Partially Filled with Liquid

We made experiments on the vibration s of a rotating shaft with a hollow rotor partially filled with liquid, and investigated especially the variation of resonance curves at the major critical speed and the effect of viscosity and specific gravity on the unstable vibration. As the result, the following are clarified. (a) A hysteresis phenomenon appeared in the resonance curve at the major critical speed. (b) The rotating speed where the resonance curve takes a maximum value becomes lower as the quantity of liquid increases. (c) The amplitude at the major critical speed changes variously depending on the volume of liquid, the initial bending of the shaft, and the unbalance of the rotor. (d) The width of the unstable region depends on the specific gravity of liquid but it is independent of the viscosity. (e) The growing rate of the unstable vibration decreases as the viscosity increases.