Session: 09-01-12 Experimental Methods

Paper Number: 81065

81065 - Model Test and Validation of the Crown Floating Offshore Wind Turbine 

Key words: floating wind turbines, hybrid testing, tuned liquid column damper, state estimator

Objective

Past projects have shown that compared to bottom fixed wind turbines, floating offshore wind turbines (FOWTs) are confronting challenges concerning power production and structural loads, especially due to the wave and wind induced floater motions. The wave loads yield extra dynamics at the tower top and base, which leads to a reduced structural lifetime and more fluctuating power production. To improve the FOWT system responses and reduce the effects induced by floater motions, it is beneficial on one hand to have a good knowledge of the current system states, on the other hand, to have extra dampers stabilizing the floater.

Methodology

Within the project Motion Reduction of a Concrete Reduced-draft spar for the Offshore floating Wind iNdustry (CROWN), a Luenberger state observer was developed to estimate the real-time motions and loads, a tuned liquid multi-column damper (TLMCD) was designed to provide extra damping in floater roll and pitch degrees of freedom. After numerical proven, a 1:36 scaled model was build and tested in the wave basin of IH Cantabria. Different load cases including system characterization and operation under wave and wind combined environment were selected. Due to the inconsistency in scaling laws of the hydrodynamics and aerodynamics, the rotor was replaced by a multi-fan system exerting equivalent aerodynamic thrust forces simulated by a numerical model on the floater, which is also called hybrid testing. Multiple sensors are installed to measure the floater motion, the mooring loads, the fluid motion inside the TLMCD etc.

Results

The test campaign was carried out successfully, which enables the comparison between the numerical and experimental models. The comparison proves the functioning of the state observer, as well as the validity of the TLMCD & FOWT coupled numerical model.

Presenting Author: Wei Yu Stuttgart Wind Energy (SWE) @ Institute of Aircraft Design, University of Stuttgart, Germany

Authors:

Wei Yu Stuttgart Wind Energy (SWE) @ Institute of Aircraft Design, University of Stuttgart, Germany
Lemmer Frank sowento GmbH
Katja Lehmann sowento GmbH
Po Wen Cheng Stuttgart Wind Energy (SWE) @ Institute of Aircraft Design, University of Stuttgart, Germany
Santiago De Guzmán Seaplace SL
Jaime Moreu Seaplace SL
Tommaso Battistella Environmental Hydraulics Institute of Cantabria