Coupled dynamic response of a tension leg platform system under waves and flow at different heading angles: An experimental study

A Tension leg platform (TLP) exhibits different movement characteristics under waves or flow. A three-dimensional (3-D) experimental investigation of the coupled dynamic response of a TLP system under different environmental conditions is presented in this paper. The TLP system includes platform, tension legs and risers. Regular and irregular waves, flow, and a combination of irregular waves and flow are employed as the environmental conditions. The influence of different heading angles on the motion responses in the in-line (IL) and cross-flow (CF) directions are presented. The motion spectra, wavelet transform, and motion trajectories are employed to analyze the time histories. Statistical analysis of motion characteristics of TLP under different environmental conditions is presented here and the most disadvantage heading angle is recommended. With an increase of reduced velocity, the flow-induced motion (FIM) of the platform first increases and then decreases, and multi-frequency time-varying coupling characteristics are presented in the cases of large reduced velocity. The FIM in this experiment and that in the towing tank are compared simultaneously. In addition, the influence of free surface waves on the FIM has been illustrated through qualitative and quantitative analysis.