Effect of shroud eccentricity on suppression of flow induced vibrations

The object of the research described was to examine the vibrational characteristics (amplitude and frequency) and the resulting drag for an eccentrically shrouded cylinder. The results revealed that an eccentricity in any direction and of any magnitude always reduces the amplitude of vibration in the subcritical flow region in comparison with that of a concentrically shrouded cylinder. This trend was terminated within the transitional region where there was a converging of the concentric and eccentric vibrational responses. The drag of the cylinder enclosed in the axial-rod shroud was found to be less than the drag of the plain cylinder in the subcritical region but the opposite effect was obtained in the transitional region. The drag was measured on the eccentrically shrouded cylinder for various upstream, lateral and downstream eccentricities and the results were compared with those for the concentrically shrouded cylinder.