OC6 Phase I: Investigating the underprediction of low-frequency hydrodynamic loads and responses of a floating wind turbine
Amy Robertson, Sébastien Gueydon, Erin E. Bachynski, Lu Wang, Jason Jonkman, Daniel Alarcón, Ervin Amet, Alec Beardsell, Paul Bonnet, B Boudet, C. Brun, Zheng Chen, Marie Féron, Dominic Forbush, Christos Galinos, Josean Galván, Philippe Gilbert, Juan Pablo Gómez, Violette Harnois, Florence Haudin, Zhiqiang Hu, Jean-Baptiste Le Dreff, Mareike Leimeister, Frank Lemmer, Haoyang Li, Graeme C. McKinnon, I. Mendikoa, Abdolmajid Moghtadaei, Stefan Netzband, Sho Oh, Antonio Pegalajar‐Jurado, Minh Nguyen, Kelley Ruehl, Paul Schünemann, Wei Shi, Hyunkyoung Shin, Yulin Si, Florian Surmont, Pau Trubat, J Qwist, S Wohlfahrt-Laymann
Abstract
Abstract Phase I of the OC6 project is focused on examining why offshore wind design tools underpredict the response (loads/motion) of the OC5-DeepCwind semisubmersible at its surge and pitch natural frequencies. Previous investigations showed that the underprediction was primarily related to nonlinear hydrodynamic loading, so two new validation campaigns were performed to separately examine the different hydrodynamic load components. In this paper, we validate a variety of tools against this new test data, focusing on the ability to accurately model the low-frequency loads on a semisubmersible floater when held fixed under wave excitation and when forced to oscillate in the surge direction. However, it is observed that models providing better load predictions in these two scenarios do not necessarily produce a more accurate motion response in a moored configuration.