OrthoSpar, a novel substructure concept for floating offshore wind turbines: physical model tests under towing conditions
DATE:
2022-02
UNIVERSAL IDENTIFIER: http://hdl.handle.net/11093/3137
EDITED VERSION: https://linkinghub.elsevier.com/retrieve/pii/S0029801821017868
UNESCO SUBJECT: 3319.99 Otras
DOCUMENT TYPE: article
ABSTRACT
An important condition of any port-assembled floating offshore wind turbine concept is the de-ballasted transport stage. As the hydrostatic and dynamic stability may vary greatly from the operational condition, it needs to be carefully investigated in early stages of the design-phase. In this work, physical modelling of the transport of the de-ballasted OrthoSpar device was carried out to determine roll and pitch RAOs, as well as load characteristics of the towing line. Towing was simulated with a stationary model being subjected to currents. To examine the influence of wave direction, a range of model orientations towards the incident waves were tested in still water and together with the simulated towing state. Roll and pitch motions were found to be highly dependent on the wave frequency and a result of a low damping ratio. The towing load amplitude was found to be influenced by the towing direction regarding the wave direction.