scholarly journals NEAR-SHORE FLOATING WAVE ENERGY CONVERTERS: APPLICATIONS FOR COASTAL PROTECTION

2011 ◽  
Vol 1 (32) ◽  
pp. 61 ◽  
Author(s):  
Piero Ruol ◽  
Barbara Zanuttigh ◽  
Luca Martinelli ◽  
Peter Kofoed ◽  
Peter Frigaard

Aim of this note is to analyse the possible application of a Wave Energy Converter (WEC) as a combined tool to protect the coast and harvest energy. Physical model tests are used to evaluate wave transmission past a near-shore floating WEC of the wave activated body type, named DEXA. Efficiency and transmission characteristics are approximated to functions of wave height, period and obliquity. Their order of magnitude are 20% and 80%, respectively. It is imagined that an array of DEXA is deployed in front of Marina di Ravenna beach (IT), a highly touristic site of the Adriatic Coast. Based on the CERC formula, long-shore sediment transport is evaluated in presence and in absence of this array of DEXAs. The sediment transport in this site is quite large and frequently changes directions during the year. The larger North directed contribution and the more persistent South directed one are similar in magnitude and almost compensate each other, with the latter only slightly prevailing. It is shown that the DEXA could be designed so that the effect on sediment transport becomes quite significant and the direction of the net transport can be reversed.

2012 ◽  
Vol 1 (33) ◽  
pp. 5 ◽  
Author(s):  
Hernan Fernandez ◽  
Gregorio Iglesias ◽  
Rodrigo Carballo ◽  
Alberte Castro ◽  
Marcos Sánchez ◽  
...  

The development of efficient, reliable Wave Energy Converters (WECs) is a prerequisite for wave energy to become a commercially viable energy source. Intensive research is currently under way on a number of WECs, among which WaveCat©—a new WEC recently patented by the University of Santiago de Compostela. In this sense, this paper describes the WaveCat concept and its ongoing development and optimization. WaveCat is a floating WEC intended for operation in intermediate water depths (50–100 m). Like a catamaran, it consists of two hulls—from which it derives its name. The difference with a conventional catamaran is that the hulls are not parallel but convergent; they are joined at the stern, forming a wedge in plan view. Physical model tests of a 1:30 model were conducted in a wave tank using both regular and irregular waves. In addition to the waves and overtopping rates, the model displacements were monitored using a non-intrusive system. The results of the physical model tests will be used to validate the 3D numerical model, which in turn will be used to optimize the design of WaveCat for best performance under a given set of wave conditions.


Author(s):  
Jennifer van Rij ◽  
Yi-Hsiang Yu ◽  
Ryan G. Coe

This study demonstrates a systematic methodology for establishing the design loads of a wave energy converter. The proposed design load methodology incorporates existing design guidelines, where they exist, and follows a typical design progression; namely, advancing from many, quick, order-of-magnitude accurate, conceptual stage design computations to a few, computationally intensive, high-fidelity, design validation simulations. The goal of the study is to streamline and document this process based on quantitative evaluations of the design loads’ accuracy at each design step and consideration for the computational efficiency of the entire design process. For the wave energy converter, loads, and site conditions considered, this study demonstrates an efficient and accurate methodology of evaluating the design loads.


2012 ◽  
Vol 1 (33) ◽  
pp. 68 ◽  
Author(s):  
Elisa Angelelli ◽  
Barbara Zanuttigh

This paper aims at investigating the efficacy of a floating farm of wave energy converters for coastal protection purposes through physical and numerical modelling. The experiments were performed in 3D conditions on a basic module consisting of two staggered lines and three devices. The numerical simulations were carried out with the software MIKE 21 BW, developed by DHI Water & Environment & Health, and were calibrated based on the experimental results. Additional configurations were tested by varying the gap long-shore width and the device alignment. Despite the model limitations, i.e. the representation of the devices as fixed porous piles, the numerical results well approximate the average measured transmission coefficient and allow to derive a complete map of the hydrodynamics around the devices.


2016 ◽  
Vol 97 ◽  
pp. 769-783 ◽  
Author(s):  
José F. Gaspar ◽  
Mojtaba Kamarlouei ◽  
Ashank Sinha ◽  
Haitong Xu ◽  
Miguel Calvário ◽  
...  

2011 ◽  
Vol 1 (32) ◽  
pp. 62 ◽  
Author(s):  
Edgar Mendoza-Baldwin ◽  
Rodolfo Silva-Casarín ◽  
Rafael Sánchez-Dirzo ◽  
Xavier Chávez-Cárdenas

This paper presents the results of exhaustive experimental work focused on evaluating the efficiency of two devices as wave energy converters and as coastal protection alternatives. The first device is a wave amplifier that by means of overtopping stores water in a reservoir where potential energy can be used to produce power. The second device, the Blow-Jet, is a novel proposal that gathers together the operation of a tapchan and a blowhole to generate an intermittent jet that can easily feed a turbine. Results show that for both devices there is a strong dependency on the wave climate but that there is a possibility of optimizing geometric designs. Transmission coefficient values obtained for the Blow-Jet point to a real chance for its use as a multi-purpose coastal structure.


Author(s):  
Lander Victor ◽  
Jens Peter Kofoed ◽  
Peter Troch

Many sea defense structures need to be adapted to the rising sea water level and changing wave climate due to global warming. The accordingly required investments open perspectives for wave energy converters (WECs) — that are built as part of the sea defense structures — to become economically viable. In this paper the average overtopping discharges q of overtopping wave energy converters built in sea defense structures are studied. Physical model tests with this type of devices have been carried out in a wave flume leading to experimentally determined values for the average overtopping discharge q. These experimental data are compared with predicted average overtopping discharges using existing empirical formulae from literature — derived mainly for sea defense structures. Overtopping WECs have small relative crest freeboard heights and smooth slopes to maximize overtopping, which is contradictive to the basic role of sea defense structures. As a consequence, the experimentally achieved average overtopping discharges are situated in a range that is not well covered by the existing traditional prediction formulae. The presented results for linear-slope overtopping WECs fill the gap between those for smooth dikes and those for plain vertical walls. The overtopping behavior in that particular range is discussed in this paper.


Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2109 ◽  
Author(s):  
Dina Silva ◽  
Eugen Rusu ◽  
C. Guedes Soares

This paper assesses the impact of a farm of wave energy converters on a nearby offshore aquaculture installation and on the nearshore dynamics. The coastal area targeted is Aguçadoura, located in the north of Portugal, where the world’s first wave farm operated in 2008. The study is focused mainly on the evaluation of the sheltering effect provided by the wave farm to the aquaculture cages. Furthermore, the possible impact on the coastal wave climate of such an energy park is also evaluated. These objectives are accomplished by performing simulations, corresponding to the wave conditions, which are more often encountered in that coastal environment. The SWAN model (Simulating WAves Nearshore) was adopted for this. Various transmission scenarios are considered to account for the impact of different types of wave converter farms on the downwave conditions. The results show that such a wave energy park might have a clear positive impact on the wave conditions fish farm installed downwave and it might also have a beneficial influence on shoreline dynamics from the perspective of coastal protection.


Author(s):  
Jørgen Harck Nørgaard ◽  
Thomas Lykke Andersen ◽  
Jens Peter Kofoed

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1137
Author(s):  
Philip Balitsky ◽  
Nicolas Quartier ◽  
Vasiliki Stratigaki ◽  
Gael Verao Fernandez ◽  
Panagiotis Vasarmidis ◽  
...  

In this study, a series of modules is integrated into a wave-to-wire (W2W) model that links a Boundary Element Method (BEM) solver to a Wave Energy Converter (WEC) motion solver which are in turn coupled to a wave propagation model. The hydrodynamics of the WECs are resolved in the wave structure interaction solver NEMOH, the Power Take-off (PTO) is simulated in the WEC simulation tool WEC-Sim, and the resulting perturbed wave field is coupled to the mild-slope propagation model MILDwave. The W2W model is run for verified for a realistic wave energy project consisting of a WEC farm composed of 10 5-WEC arrays of Oscillating Surging Wave Energy Converters (OSWECs). The investigated WEC farm is modelled for a real wave climate and a sloping bathymetry based on a proposed OSWEC array project off the coast of Bretagne, France. Each WEC array is arranged in a power-maximizing 2-row configuration that also minimizes the inter-array separation distance d x and d y and the arrays are located in a staggered energy maximizing configuration that also decreases the along-shore WEC farm extent. The WEC farm power output and the near and far-field effects are simulated for irregular waves with various significant wave heights wave peak periods and mean wave incidence directions β based on the modelled site wave climatology. The PTO system of each WEC in each farm is modelled as a closed-circuit hydraulic PTO system optimized for each set of incident wave conditions, mimicking the proposed site technology, namely the WaveRoller® OSWEC developed by AW Energy Ltd. The investigation in this study provides a proof of concept of the proposed W2W model in investigating potential commercial WEC projects.


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