Comparative study of the influence of a wave energy converter site on the wave field of Laguna, SC, Brazil

2019 ◽  
Vol 31 ◽  
pp. 262-272 ◽  
Author(s):  
Phelype Haron Oleinik ◽  
Thaísa Beloti Trombetta ◽  
Ricardo Cardoso Guimarães ◽  
Eduardo de Paula Kirinus ◽  
Wiliam Correa Marques
Keyword(s):  
Comparative Study ◽  
Wave Field ◽  
Wave Energy ◽  
Wave Energy Converter ◽  
Energy Converter

scholarly journals A Novel Method for Estimating Wave Energy Converter Performance in Variable Bathymetry Regions and Applications

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2092 ◽  
Author(s):  
Kostas Belibassakis ◽  
Markos Bonovas ◽  
Eugen Rusu
Keyword(s):  
Wave Field ◽  
Wave Energy ◽  
Water Waves ◽  
Bottom Topography ◽  
Wave Energy Converter ◽  
Diffraction Radiation ◽  
Floating Bodies ◽  
Energy Converter ◽  
Coupled Mode ◽  
Energy Absorbers

A numerical model is presented for the estimation of Wave Energy Converter (WEC) performance in variable bathymetry regions, taking into account the interaction of the floating units with the bottom topography. The proposed method is based on a coupled-mode model for the propagation of the water waves over the general bottom topography, in combination with a Boundary Element Method for the treatment of the diffraction/radiation problems and the evaluation of the flow details on the local scale of the energy absorbers. An important feature of the present method is that it is free of mild bottom slope assumptions and restrictions and it is able to resolve the 3D wave field all over the water column, in variable bathymetry regions including the interactions of floating bodies of general shape. Numerical results are presented concerning the wave field and the power output of a single device in inhomogeneous environment, focusing on the effect of the shape of the floater. Extensions of the method to treat the WEC arrays in variable bathymetry regions are also presented and discussed.

Measurement of the Effect of Power Absorption in the Lee of a Wave Energy Converter

2009 ◽  
Author(s):  
Ian G. C. Ashton ◽  
Lars Johanning ◽  
Brian Linfoot
Keyword(s):  
Wave Field ◽  
Wave Energy ◽  
Ocean Waves ◽  
Wave Climate ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
Wave Measurements ◽  
Temporal And Spatial Variability ◽  
Power Capture ◽  
Local Wave

Monitoring the effect of floating wave energy converter (WEC) devices on the surrounding wave field will be an important tool for monitoring impacts on the local wave climate and coastlines. Measurement will be hampered by the natural variability of ocean waves and the complex response of WEC devices, causing temporal and spatial variability in the effects. Measurements taken during wave tank tests at MARINTEK are used to analyse the effectiveness of point wave measurements at resolving the influence of an array of WEC on the local wave conditions. The variability of waves is measured in front and in the lee of a device, using spectral analysis to identify changes to the incident wave field due to the operating WEC. The power capture and radiation damping are analysed in order to predict the measured changes. Differences in the wave field across the device are clearly observable in the frequency domain. However, they do not unanimously show a reduction in wave energy in the lee of a device and are not well predicted by measured power capture.

Comparative Study of Wave Load Effects for Two Wave Energy Converter Concepts

2009 ◽  
Author(s):  
Reza Taghipour ◽  
Arswendy Arswendy ◽  
Torgeir Moan
Keyword(s):  
Comparative Study ◽  
Wave Energy ◽  
Transfer Functions ◽  
Bending Moment ◽  
Wave Energy Converter ◽  
Wave Load ◽  
Energy Converter ◽  
Supporting Structure ◽  
Hydraulic Machinery ◽  
Load Effects

This paper deals with a comparative study of hydrodynamic and structural performance for two different concepts of the FO3 wave energy converter (WEC). The WEC consists of 22 bodies: a semisubmersible platform as supporting structure and 21 buoys as point absorbers. The buoys can slide along some guides that are attached to the deck of the platform. The power is produced from the relative motion between the buoys and the supporting structure by means of hydraulic machinery on the deck. In the first FO3 concept, known as the Alternative 1 FO3, the supporting structure is a ring pontoon semisubmersible platform. The other concept is known as the Alternative 2 FO3, in which the Alternative 1’s semisubmersible platform is replaced by a cylindrical-pontoon platform. As one of the scenarios which is considered in this paper, the buoys are locked at their design draft. The objective is to compare the motions and the axial force and bending moment transfer functions in the column- and guide-deck connections for these two concepts.

scholarly journals Experimental Measurement of Wave Field Variations around Wave Energy Converter Arrays

2017 ◽  
Vol 9 (1) ◽  
pp. 70 ◽  
Author(s):  
Louise O’Boyle ◽  
Björn Elsäßer ◽  
Trevor Whittaker
Keyword(s):  
Wave Field ◽  
Wave Energy ◽  
Experimental Measurement ◽  
Wave Energy Converter ◽  
Energy Converter

scholarly journals Analyzing the Near-Field Effects and the Power Production of an Array of Heaving Cylindrical WECs and OSWECs Using a Coupled Hydrodynamic-PTO Model

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3489 ◽  
Author(s):  
Philip Balitsky ◽  
Nicolas Quartier ◽  
Gael Verao Fernandez ◽  
Vasiliki Stratigaki ◽  
Peter Troch
Keyword(s):  
Numerical Model ◽  
Wave Field ◽  
Wave Energy ◽  
Power Output ◽  
Near Field ◽  
Power Production ◽  
Wave Energy Converter ◽  
Floating Body ◽  
Energy Converter ◽  
Field Effects

The Power Take-Off (PTO) system is the key component of a Wave Energy Converter (WEC) that distinguishes it from a simple floating body because the uptake of the energy by the PTO system modifies the wave field surrounding the WEC. Consequently, the choice of a proper PTO model of a WEC is a key factor in the accuracy of a numerical model that serves to validate the economic impact of a wave energy project. Simultaneously, the given numerical model needs to simulate many WEC units operating in close proximity in a WEC farm, as such conglomerations are seen by the wave energy industry as the path to economic viability. A balance must therefore be struck between an accurate PTO model and the numerical cost of running it for various WEC farm configurations to test the viability of any given WEC farm project. Because hydrodynamic interaction between the WECs in a farm modifies the incoming wave field, both the power output of a WEC farm and the surface elevations in the ‘near field’ area will be affected. For certain types of WECs, namely heaving cylindrical WECs, the PTO system strongly modifies the motion of the WECs. Consequently, the choice of a PTO system affects both the power production and the surface elevations in the ‘near field’ of a WEC farm. In this paper, we investigate the effect of a PTO system for a small wave farm that we term ‘WEC array’ of 5 WECs of two types: a heaving cylindrical WEC and an Oscillating Surge Wave Energy Converter (OSWEC). These WECs are positioned in a staggered array configuration designed to extract the maximum power from the incident waves. The PTO system is modelled in WEC-Sim, a purpose-built WEC dynamics simulator. The PTO system is coupled to the open-source wave structure interaction solver NEMOH to calculate the average wave field η in the ‘near-field’. Using a WEC-specific novel PTO system model, the effect of a hydraulic PTO system on the WEC array power production and the near-field is compared to that of a linear PTO system. Results are given for a series of regular wave conditions for a single WEC and subsequently extended to a 5-WEC array. We demonstrate the quantitative and qualitative differences in the power and the ‘near-field’ effects between a 5-heaving cylindrical WEC array and a 5-OSWEC array. Furthermore, we show that modeling a hydraulic PTO system as a linear PTO system in the case of a heaving cylindrical WEC leads to considerable inaccuracies in the calculation of average absorbed power, but not in the near-field surface elevations. Yet, in the case of an OSWEC, a hydraulic PTO system cannot be reduced to a linear PTO coefficient without introducing substantial inaccuracies into both the array power output and the near-field effects. We discuss the implications of our results compared to previous research on WEC arrays which used simplified linear coefficients as a proxy for PTO systems.

Comparative Study of Hydrodynamic Responses of Two Combined Wind Turbine and Wave Energy Converter Systems Under Typical Operational Sea Cases

2018 ◽  
Author(s):  
Nianxin Ren ◽  
Ying Zhu ◽  
Zhe Ma ◽  
Hongbo Wu
Keyword(s):  
Comparative Study ◽  
Wind Turbine ◽  
Contact Force ◽  
Wave Energy ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
Extreme Loads ◽  
New Strategy ◽  
Floating System ◽  
The Time Domain

In present work, two combined wind turbine (WT) and wave energy converter (WEC) systems have been concerned. One is a fixed-bottom system, referred as “MWWC” (monopile-WT-WEC combination); the other is a floating system, referred as “TWWC” (TLP-WT-WEC-combination). Comparative study of the hydrodynamic responses of the two combined systems has been done by numerical simulations in the time domain. Hydrodynamic loads of the supporting structures and the WEC are calculated by the AQWA code, which is available for modeling multi-body systems including both mechanical and hydrodynamic couplings between the supporting tower and the WEC floater. Firstly, the effect of different power-take-off (PTO) parameters, wave periods and the displacements of the WEC on the performance of the WEC’s wave energy production of the two combined systems under typical wave cases has been investigate, and preliminary optimal values for the PTO damping stiffness of the two combined systems have been obtained and compared; secondly, the effect of the horizontal contact force between the supporting tower and the additional WEC floater of the two combined systems have been further investigated, which is important for both the fatigue and extreme loads design of the supporting tower. Finally, a new strategy for MWWC system by adding horizontal PTO dampers between the supporting tower and the WEC floater has been proposed and investigated, which is helpful for both reducing the horizontal contact force and using the relative horizontal motion to produce power.

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