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Floating substructures for wind turbines are commonly credited for enabling the offshore wind industry, so far focused on fixed substructures, to expand into deeper waters. As per Arent et al. (Improved offshore wind resource assessment in global climate stabilization scenarios, [4]), 77% of global offshore wind potential is located in water depths deeper than 60 m. However, floating substructures do not yet meet the market expectations with regard to LCOE. By integrating new materials as well as modularity into the design, the costs of the tension leg platform (TLP) development presented in this pater have been significantly reduced. Pre-stressed Ultra-High-Performance-Concrete (UHPC) pipes will be used for this sub-structure. The buoyancy bodies will be fabricated using concrete shell elements known from tunnel engineering. The use of casted iron for the nodes and the Transition Piece (TP) leads to further advantages regarding design and costs. All components are designed for transportability (e.g. via railway) in order to ensure a high level of flexibility within the supply chain. The structural design has been calculated to support turbines of up to 6 MW rated power and more. In October 2017, a scaled model (1:50) of the new substructure design for use with a 6 MW turbine was successfully exposed to wind and wave loads at the Ocean Engineering Tank of the Ecole Centrale de Nantes (ECN). In June 2018, a second measurement campaign was started, and in September 2018 a third campaign will be run to verify the transport & installation process. Th presentation and paper will focus on the TLP design as well as on the model fabrication and scaling. Furthermore, measurement results from the ECN test will be presented. Therefore, the presentation will introduce the measurement setup as well as the measurement types to verify the simulation model. Finally, the verification of the simulation model with the measurements will be highlighted.

The main objective of the Offshore Code Comparison Collaboration Continuation, with Correlation (OC5) project, is validation of aero-hydro-servo-elastic simulation tools for offshore wind turbines (OWTs) through comparison of simulated results to the response data of physical systems. Phase III of the OC5 project analyzes the Senvion 5M wind turbine supported by the OWEC Quattropod from the alpha ventus offshore wind farm. This paper shows results of the verification of the OWT models (code-to-code comparison). A subsequent publication will focus on their validation (comparison of simulated results to measured physical system response data). Based on the available data, the participants of Phase III set up numerical models of the OWT in their simulation tools. It was necessary to verify and to tune these models. The verification and tuning were performed against an OWT model available at the University of Stuttgart – Stuttgart Wind Energy (SWE) and documentation provided by Senvion and OWEC Tower. A very good match was achieved between the results from the reference SWE model and models set up by OC5 Phase III participants.

Floating wind turbine systems will play an important role for a sustainable energy supply in the future. The dynamic behavior of such systems is governed by strong couplings of aerodynamic, structural mechanic and hydrodynamic effects. To examine these effects scaled tank tests are an inevitable part of the design process of floating wind turbine systems. Normally Froude scaling is used in tank tests. However, using Froude scaling also for the wind turbine rotor will lead to wrong aerodynamic loads compared to the full-scale turbine. Therefore the paper provides a detailed description of designing a modified scaled rotor blade mitigating this problem. Thereby a focus is set on preserving the tip speed ratio of the full scale turbine, keeping the thrust force behavior of the full scale rotor also in model scale and additionally maintaining the power coefficient between full scale and model scale. This is achieved by completely redesigning the original blade using a different airfoil. All steps of this redesign process are explained using the example of the generic DOWEC 6MW wind turbine. Calculations of aerodynamic coefficients are done with the software tools XFoil and AirfoilPrep and the resulting thrust and power coefficients are obtained by running several simulations with the software AeroDyn.

This paper presents a model-based tracking control design for a mechanism dedicated to accurately reproduce the breathing-induced motion of a human lung tumour. A lung tumour mimic model should perform the same smooth motion as a real one in a human body during inhalation and exhalation. For this purpose, a 3-dimensional mechanism with three pneumatically driven axes has been developed and built up. The proposed control structure represents a cascaded flatness-based tracking control structure: In the fast inner loops, the chambers pressures of the pneumatic cylinders are controlled, whereas the outer loops are related to the position control of the cylinders. Furthermore, sliding mode observers are employed for each cylinder to estimate the corresponding states and a lumped disturbance force. The proposed overall control structure has been implemented and successfully validated on an innovative test rig.