Experimental investigation of the vortex-induced motion of tension leg platform system with suppression system under current

Abstract

The vortex-induced motion (VIM) of a tension leg platform (TLP) and vortex-induced vibration (VIV) of tension legs and risers occur only under the action of water flow. The VIM results in a high amplitude motion in the cross-flow (CF) direction, and the VIV leads to fatigue failure of the tension legs and risers. A three-dimensional (3D) physical model investigation was conducted on the overall dynamic response of the platform and acceleration at different positions of the tension legs in the in-line (IL) and CF directions. Different lengths of the splitter plate behind the TLP columns were observed, and the suppression effect of the VIM at six flow velocities was investigated. The experimental results indicated the obvious VIM phenomenon of the platform without the splitter plate, and multi-frequency time-varying coupling characteristics were observed when the heading angle was 45°. Furthermore, the results revealed that the VIM phenomenon of the platform was evidently suppressed, in amplitude and frequency, and the force coefficients are reduced significantly, after the splitter plates were arranged behind each column of the platform. However, the splitter plate slightly affected the VIV of the tension legs.