Vibrations of a Circular Cylinder Immersed Perpendicular to a Two-Phase Air-Water Bubbly Flow : 3rd Report, Response Characteristics of In-Line Vibrations and Vibration Reduction and Excitation due to a Bubbly Flow

Abstract

We experimentally examined the response characteristics of a circular cylinder's in-line vibrations induced by a two-phase air-water cross flow with respect to the flow velocity, void fraction, and air bubble size. Experiments showed the following major results : (1) Vibrational response magnitude increased rapidly, with the two-phase flow's void fraction volumetrically exceeding about 10% for each flow velocity. (2) This response was comparatively small and less dependent on the void fraction for void fractions under 10%. (3) Air bubbles in the two-phase flow drastically reduced in-line vibrations when the reduced velocity was about 2 and the void fraction was less than 10%. (4) Air bubble size slightly influenced response characteristics and the reduction in vibration.