The Use of Air-Bubble Spoilers To Suppress Vortex-Induced Vibrations of Risers

Abstract

Summary For this paper, we considered the feasibility of a bubble spoiler as a vortex-suppression device. The introduction of bubbles in the flow reduced the dynamic forces on the riser by destroying the vortex-shedding structure. We constructed a semiempirical equation relating the reduction of the vibration amplitude to the amount of air required. Then we considered the effectiveness of bubble spoilers as a suppression device by investigating the dynamic response of a typical jack-up drilling riser for various suppression scenarios. We found that the volume of air required to effectively suppress the vortices was about 2.0 m3/s at 500 kPa.