Abstract
A truncated conical rotor undergoes unstable vibration when it is partially immersed in water and driven at a supercritical speed. The unstable vibration is a forward whirl and occurs at a limited range of rotation speed and rotor immersion in water. A vibration suppression ring having 4 or 8 radial fins is installed concentrically to the truncated conical rotor, to investigate experimentally the performance of vibration suppression for a variety of combinations of the gap between the rotor and radial fins and the degree of radial fin submersion in water. Experiments show that a ring having 4 radial fins installed parallel to the diagonal of a rectangular water tank is most effective for vibration suppression when the gap is almost equal to half the rotor diameter and the fin submersion equals the rotor's immersion in water. We achieved vibration suppression to one tenth of that obtained for cases where no ring was used.
