VIV Response of a Flexible Cylinder Under Locally Strong Sheared Flow

The vortex-induced vibration (VIV) analysis of a flexible riser under locally strong sheared flow is presented. The riser model is made of Teflon and has 9.5m length, 0.0127m diameter, and 0.001m thickness. 11 2-dimensional accelerometers are installed along the riser. The experiment is conducted at the model basin in the University of Tokyo whose width is 10m, depth is 5m, and length is 50m. The model is installed at about 30 degree of slope and submerged by 99% of the overall length. Locally strong sheared flow is made by adding accelerated flow generated by an impeller-type accelerator submerged by 0.72m to uniform current. The applied top tensions are 2–8kgf by 2kgf interval. The results of CFD calculation in the similar condition using discrete vortex method (DVM) are also presented.