Optimal Dimensions of a Semisubmersible Floating Platform for a 10 MW Wind Turbine

Abstract

In this paper, an optimal semisubmersible platform is sought considering two key geometry variables: the diameter of the outer cylinders and their radial distance from the platform centre. The goal is to identify a platform configuration able to most efficiently contrast the combined wind-wave action, keeping the platform dimensions as small as possible. The amplitude of the Response Amplitude Operator (RAO) peaks and the integral area of the RAOs in a range of excited frequencies for the selected degrees of freedom are chosen as targets to be minimised. Through an efficient frequency domain simulation approach, we show that upscaling techniques proposed in the literature may lead to overdesigned platforms and that smaller and more performing platforms can be identified. In particular, the optimised platform shows a reduction of about 51% in parked and 54% in power production of the heave RAO peak, and a reduction of about 37% in parked and 50% in power production of the pitch RAO.

A review of numerical modelling and optimisation of the floating support structure for offshore wind turbines

“…MoWiT was verified with an overall good agreement with OC3 results in (Leimeister et al 2020a). Established codes such as FAST are often chosen as reference for newly developed codes (Ferri et al 2020(Ferri et al , 2021Lemmer et al 2020a;Karimi et al 2017). The coupled model ANSYS AQWA/PHATAS was verified against an uncoupled frequency-domain model in Huijs et al (2014).…”

“…The numerical model has shown a good prediction of the response magnitude to wind and wave forces even for the linearized model compared to a high-fidelity code such as FAST (National Renewable Energy Laboratory 2022a). Two key design parameters of the DTU 10 MW platform were optimised to minimise the peaks and the areas of the heave and pitch RAOs in Ferri et al (2020Ferri et al ( , 2021. The optimal configuration resulted smaller and with a better performance in surge, heave and pitch compared to the OC4 5MW upscaled platform.…”

Influence of Clumps-Weighted Moorings on a Spar Buoy Offshore Wind Turbine

“…However, when high efficiency is required as in the present case, the potential-flow theory together with the assumption of small waves and small body motion represent an acceptable trade-off between accuracy and efficiency. It is noted that purely frequency domain models [18,44,45] are even more appealing due to their higher efficiency.…”

Preliminary Sizing and Optimization of Semisubmersible Substructures for Future Generation Offshore Wind Turbines

“…The resulting optimum design is likely to depend on the optimization method, the selected design load case, and objectives. In another study by Ferri et al [6], a reference semi-submersible platform designed for a 5 MW turbine was upscaled to host a 10 MW turbine using a parametric study. The study employed a frequency-domain model based on a boundary element solver for modeling hydrodynamic loads and linearized aerodynamic, viscous and mooring loads.…”