Numerical and experimental studies of a multi-purpose floating TLP structure for combined wind and wave energy exploitation

Abstract

This paper summarizes the coupled hydro-aero-elastic analysis of a multi-purpose floating structure suitable for offshore wind and wave energy exploitation. The analysis incorporates properly the solutions of the diffraction and the pressure- and motion- dependent radiation problems around the floating structure and the aerodynamics of a 5 MW Wind Turbine (WT). Finite water depths are considered, the structure being floating under the action of regular surface waves. The platform encompasses three hydrodynamically interacting Oscillating Water Column (OWC) devices consisting of concentric vertical cylinders, moored through tensioned tethers in a TLP concept. Details concerning the numerical and experimental modelling of the system are presented and the numerical results are compared against experimental data.

New horizons for the Panhellenic Symposium of Oceanography & Fisheries

“…• The paper presented by Mazarakos et al (2019) provides results from coupled hydro-aero-elastic analysis of a multi-purpose floating structure, specifically designed for offshore wind and wave energy exploitation, by comparing experimental data with numerical ones.…”

Hydrodynamic Investigation of a Dual-Cylindrical OWC Wave Energy Converter Integrated into a Fixed Caisson Breakwater

“…Spyros A. Mavrakos et al [17] investigated the hydrodynamic forces and motions on the concentric vertical cylinders, a series of experiments concerning concentric cylinders arrangements were conducted to study the first-and second-order exciting wave forces and wave elevations at specific locations around the bodies. Thomas Mazarakos et al [18] focused on the hydro-aero-elastic coupling analysis of the multipurpose floating structures for offshore wind and wave energy exploitation, the problems of diffraction and motion-dependent radiation problems around the floating structure have been investigated. Deng et al [19] numerically investigated an OWC with a V-shaped channel, and results show that the wing walls can significantly increase the conversion efficiency of the OWC.…”

Hydro-aero-elastic analysis of offshore wind turbines

“…The floater is symmetric about both axis x=0 and y=0 and so the unknowns of the problem can be reduced to one quarter. In addition, because of the cylindrical shape, only 2 of Similar comparisons between RAOs predicted using frequency domain and time domain methods can be found in [166], for the OC3 spar buoy and in [44,120,121] for a TLP floater. In the latter case, the roll and the pitch modes of the floater are strongly coupled with the two bending modes of the tower in the fore-aft and the lateral direction.…”

“…normal to rotor disk, pre-sweep: tangential to rotor disk) has been studied with respect to the reduction of the blade loading. Also hGAST has been used in [120] for the modeling of a TLP floater, while in [121] the coupled analysis of the TLP floating WT with an Oscillating Water Column (OWC) device for wave energy extraction has been performed. Finally in [44] the 2 nd order hydrodynamic loads using Newman's approximation have been introduced and their effect has been assessed compared to the first order wave exciting loads.…”

“…The coupled dynamic behavior of floating wind turbines can be analyzed over the range of the wave frequencies by adding the contribution of the wind turbine and the mooring lines in the coupled dynamic equations of the floater motion, following a linearization process. More specifically, additional mass, damping and stiffness matrices contribute the aerodynamic, gravity and inertia-gyroscopic loads of the wind turbine and the mooring lines [44,120,121]. In this respect, the present method can be used for the design of a floating support structure carrying a wind turbine.…”